Senior Software Engineer jobs at Klaviyo

Job Description At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you're a close but not exact match with the description, we hope you'll still consider applying. Want to learn more about life at Klaviyo? Visit careers.klaviyo.com to see how we empower creators to own their own destiny. At Klaviyo, we believe the future of software lies not in productivity tools for human users but in systems that do the hard work for them. We've built the infrastructure and applications that power the interface between businesses and consumers - supporting over 167,000 customers, billions of consumer profiles, and hundreds of billions of customer interactions. Now, we're building the next generation of AI agents that can automatically create, execute, and optimize marketing and customer experience strategies for any business. As a Senior Software Engineer at Klaviyo on the Marketing Agent team, you'll play a key role in designing and building the system that autonomously creates and executes high impact marketing strategies on behalf of our customers. Partnering closely with product managers and technical product owners, you'll help define scope, translate ideas into practical implementations, and build intuitive tools that delight our customers. This role is primarily backend, with a strong focus on crafting robust and maintainable AI powered systems that deliver high quality strategies and marketing content that's ready to use to our customers. There are ample opportunities for growth given the scope of this role and the team's central role in Klaviyo's product. How you'll make a difference: You will dramatically increase ROI for Klaviyo customers by automating most of the marketing process for them. You will lead and design the next generation of agentic systems at Klaviyo, pushing the frontier of AI capabilities. You will collaborate with AI Engineers and AI Infra Engineers to ensure our system consistently produces high quality outputs at low latency. You will leverage your experience to mentor and level up junior team members on engineering best practices and patterns. You will transform workflows by putting AI at the center, building smarter systems and ways of working from the ground up. Who you are: A proven track record of building high-quality products and systems, with pride in writing clean, high-quality code. 7+ years of experience in a software engineering role. Experience leading projects and being accountable for their outcomes. Experience mentoring team members or driving initiatives that help the team learn new skills. Experience conducting code reviews and running a robust testing cycle. Experience working in agile, fast-paced environments. Proficient in Python and modern web stack components such as FastAPI, Django, MySQL, Postgres. Experience working in cloud environments (AWS preferred). You've already experimented with AI in work or personal projects, and you're excited to dive in and learn fast. You're hungry to responsibly explore new AI tools and workflows, finding ways to make your work smarter and more efficient. Nice to have: Prior work experience with AI tools such as Arize, Langgraph, Langchain Prior work experience building with LLMs such as GPT, Gemini, Claude We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025. Please see the independent bias audit report covering our use of Covey here Massachusetts Applicants: It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability. Our salary range reflects the cost of labor across various U.S. geographic markets. The range displayed below reflects the minimum and maximum target salaries for the position across all our US locations. The base salary offered for this position is determined by several factors, including the applicant's job-related skills, relevant experience, education or training, and work location. In addition to base salary, our total compensation package may include participation in the company's annual cash bonus plan, variable compensation (OTE) for sales and customer success roles, equity, sign-on payments, and a comprehensive range of health, welfare, and wellbeing benefits based on eligibility. Your recruiter can provide more details about the specific salary/OTE range for your preferred location during the hiring process. Base Pay Range For US Locations:$152,000-$228,000 USD Get to Know Klaviyo We're Klaviyo (pronounced clay-vee-oh). We empower creators to own their destiny by making first-party data accessible and actionable like never before. We see limitless potential for the technology we're developing to nurture personalized experiences in ecommerce and beyond. To reach our goals, we need our own crew of remarkable creators-ambitious and collaborative teammates who stay focused on our north star: delighting our customers. If you're ready to do the best work of your career, where you'll be welcomed as your whole self from day one and supported with generous benefits, we hope you'll join us. AI fluency at Klaviyo includes responsible use of AI (including privacy, security, bias awareness, and human-in-the-loop). We provide accommodations as needed. By participating in Klaviyo's interview process, you acknowledge that you have read, understood, and will adhere to our Guidelines for using AI in the Klaviyo interview Process. For more information about how we process your personal data, see our Job Applicant Privacy Notice. Klaviyo is committed to a policy of equal opportunity and non-discrimination. We do not discriminate on the basis of race, ethnicity, citizenship, national origin, color, religion or religious creed, age, sex (including pregnancy), gender identity, sexual orientation, physical or mental disability, veteran or active military status, marital status, criminal record, genetics, retaliation, sexual harassment or any other characteristic protected by applicable law. IMPORTANT NOTICE: Our company takes the security and privacy of job applicants very seriously. We will never ask for payment, bank details, or personal financial information as part of the application process. All our legitimate job postings can be found on our official career site. Please be cautious of job offers that come from non-company email addresses (@klaviyo.com), instant messaging platforms, or unsolicited calls. By clicking "Submit Application" you consent to Klaviyo processing your Personal Data in accordance with our Job Applicant Privacy Notice. If you do not wish for Klaviyo to process your Personal Data, please do not submit an application. You can find our Job Applicant Privacy Notice here and here (FR).

At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you're a close but not exact match with the description, we hope you'll still consider applying. Want to learn more about life at Klaviyo? Visit careers.klaviyo.com to see how we empower creators to own their own destiny. About the Role Our team is looking for a Senior Full Stack Engineer to lead key initiatives that will enhance our product offerings and support our company's growth. In this role, you'll play a crucial part in shaping outcomes by developing innovative end-to-end solutions using both front-end and back-end technologies. You'll optimize existing products and create new solutions that redefine what's possible for our customers. As a Senior Engineer, you'll tackle complex challenges, develop multiple solutions, and evaluate business and technical trade-offs to determine the best path forward. You'll also act as a leader and mentor, and drive key technology decisions. Additionally, you'll be responsible for deploying well-designed, thoroughly tested solutions that ensure reliability and performance. The New Products team drives Klaviyo's most ambitious innovations-creating and scaling the company's boldest new bets. As a nimble group with a flat structure and fast-moving culture, we prioritize simplicity, speed, and impact. Every team member is expected to take radical ownership-rolling up their sleeves, collaborating across disciplines, and pushing beyond traditional role boundaries to make things happen. Success in this role means delivering exceptional work that sets the standard for velocity and results company-wide, while helping shape Klaviyo's future through experimentation, creativity, and executional excellence. What We're Looking For A proven track record of building high-quality products and systems, with pride in writing clean, high-quality code. 7+ years of experience in a software engineering role. Strong experience developing end-to-end software solutions or extensive experience with both front-end and back-end technologies. Experience leading projects and being accountable for their outcomes. Experience mentoring team members or driving initiatives that help the team learn new skills. Experience conducting code reviews and running a robust testing cycle. Experience working in agile, fast-paced environments. You've already experimented with AI in work or personal projects, and you're excited to dive in and learn fast. You're hungry to responsibly explore new AI tools and workflows, finding ways to make your work smarter and more efficient. Transform workflows by putting AI at the center, building smarter systems and ways of working from the ground up. Nice to Have Skills with Python and related technologies Skills with React and related technologies Experience developing digital marketing or customer data software solutions. Experience with machine learning. Experience building cloud-native solutions, ideally with AWS. We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025. Please see the independent bias audit report covering our use of Covey here Massachusetts Applicants: It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability. Our salary range reflects the cost of labor across various U.S. geographic markets. The range displayed below reflects the minimum and maximum target salaries for the position across all our US locations. The base salary offered for this position is determined by several factors, including the applicant's job-related skills, relevant experience, education or training, and work location. In addition to base salary, our total compensation package may include participation in the company's annual cash bonus plan, variable compensation (OTE) for sales and customer success roles, equity, sign-on payments, and a comprehensive range of health, welfare, and wellbeing benefits based on eligibility. Your recruiter can provide more details about the specific salary/OTE range for your preferred location during the hiring process. Base Pay Range For US Locations:$152,000-$228,000 USD Get to Know Klaviyo We're Klaviyo (pronounced clay-vee-oh). We empower creators to own their destiny by making first-party data accessible and actionable like never before. We see limitless potential for the technology we're developing to nurture personalized experiences in ecommerce and beyond. To reach our goals, we need our own crew of remarkable creators-ambitious and collaborative teammates who stay focused on our north star: delighting our customers. If you're ready to do the best work of your career, where you'll be welcomed as your whole self from day one and supported with generous benefits, we hope you'll join us. AI fluency at Klaviyo includes responsible use of AI (including privacy, security, bias awareness, and human-in-the-loop). We provide accommodations as needed. By participating in Klaviyo's interview process, you acknowledge that you have read, understood, and will adhere to our Guidelines for using AI in the Klaviyo interview Process. For more information about how we process your personal data, see our Job Applicant Privacy Notice. Klaviyo is committed to a policy of equal opportunity and non-discrimination. We do not discriminate on the basis of race, ethnicity, citizenship, national origin, color, religion or religious creed, age, sex (including pregnancy), gender identity, sexual orientation, physical or mental disability, veteran or active military status, marital status, criminal record, genetics, retaliation, sexual harassment or any other characteristic protected by applicable law. IMPORTANT NOTICE: Our company takes the security and privacy of job applicants very seriously. We will never ask for payment, bank details, or personal financial information as part of the application process. All our legitimate job postings can be found on our official career site. Please be cautious of job offers that come from non-company email addresses (@klaviyo.com), instant messaging platforms, or unsolicited calls. By clicking "Submit Application" you consent to Klaviyo processing your Personal Data in accordance with our Job Applicant Privacy Notice. If you do not wish for Klaviyo to process your Personal Data, please do not submit an application. You can find our Job Applicant Privacy Notice here and here (FR).

Job Description At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you're a close but not exact match with the description, we hope you'll still consider applying. Want to learn more about life at Klaviyo? Visit careers.klaviyo.com to see how we empower creators to own their own destiny. About the Role Our team is looking for a Senior Full Stack Engineer to lead key initiatives that will enhance our product offerings and support our company's growth. In this role, you'll play a crucial part in shaping outcomes by developing innovative end-to-end solutions using both front-end and back-end technologies. You'll optimize existing products and create new solutions that redefine what's possible for our customers. As a Senior Engineer, you'll tackle complex challenges, develop multiple solutions, and evaluate business and technical trade-offs to determine the best path forward. You'll also act as a leader and mentor, and drive key technology decisions. Additionally, you'll be responsible for deploying well-designed, thoroughly tested solutions that ensure reliability and performance. The New Products team drives Klaviyo's most ambitious innovations-creating and scaling the company's boldest new bets. As a nimble group with a flat structure and fast-moving culture, we prioritize simplicity, speed, and impact. Every team member is expected to take radical ownership-rolling up their sleeves, collaborating across disciplines, and pushing beyond traditional role boundaries to make things happen. Success in this role means delivering exceptional work that sets the standard for velocity and results company-wide, while helping shape Klaviyo's future through experimentation, creativity, and executional excellence. What We're Looking For A proven track record of building high-quality products and systems, with pride in writing clean, high-quality code. 7+ years of experience in a software engineering role. Strong experience developing end-to-end software solutions or extensive experience with both front-end and back-end technologies. Experience leading projects and being accountable for their outcomes. Experience mentoring team members or driving initiatives that help the team learn new skills. Experience conducting code reviews and running a robust testing cycle. Experience working in agile, fast-paced environments. You've already experimented with AI in work or personal projects, and you're excited to dive in and learn fast. You're hungry to responsibly explore new AI tools and workflows, finding ways to make your work smarter and more efficient. Transform workflows by putting AI at the center, building smarter systems and ways of working from the ground up. Nice to Have Skills with Python and related technologies Skills with React and related technologies Experience developing digital marketing or customer data software solutions. Experience with machine learning. Experience building cloud-native solutions, ideally with AWS. We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025. Please see the independent bias audit report covering our use of Covey here Massachusetts Applicants: It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability. Our salary range reflects the cost of labor across various U.S. geographic markets. The range displayed below reflects the minimum and maximum target salaries for the position across all our US locations. The base salary offered for this position is determined by several factors, including the applicant's job-related skills, relevant experience, education or training, and work location. In addition to base salary, our total compensation package may include participation in the company's annual cash bonus plan, variable compensation (OTE) for sales and customer success roles, equity, sign-on payments, and a comprehensive range of health, welfare, and wellbeing benefits based on eligibility. Your recruiter can provide more details about the specific salary/OTE range for your preferred location during the hiring process. Base Pay Range For US Locations:$152,000-$228,000 USD Get to Know Klaviyo We're Klaviyo (pronounced clay-vee-oh). We empower creators to own their destiny by making first-party data accessible and actionable like never before. We see limitless potential for the technology we're developing to nurture personalized experiences in ecommerce and beyond. To reach our goals, we need our own crew of remarkable creators-ambitious and collaborative teammates who stay focused on our north star: delighting our customers. If you're ready to do the best work of your career, where you'll be welcomed as your whole self from day one and supported with generous benefits, we hope you'll join us. AI fluency at Klaviyo includes responsible use of AI (including privacy, security, bias awareness, and human-in-the-loop). We provide accommodations as needed. By participating in Klaviyo's interview process, you acknowledge that you have read, understood, and will adhere to our Guidelines for using AI in the Klaviyo interview Process. For more information about how we process your personal data, see our Job Applicant Privacy Notice. Klaviyo is committed to a policy of equal opportunity and non-discrimination. We do not discriminate on the basis of race, ethnicity, citizenship, national origin, color, religion or religious creed, age, sex (including pregnancy), gender identity, sexual orientation, physical or mental disability, veteran or active military status, marital status, criminal record, genetics, retaliation, sexual harassment or any other characteristic protected by applicable law. IMPORTANT NOTICE: Our company takes the security and privacy of job applicants very seriously. We will never ask for payment, bank details, or personal financial information as part of the application process. All our legitimate job postings can be found on our official career site. Please be cautious of job offers that come from non-company email addresses (@klaviyo.com), instant messaging platforms, or unsolicited calls. By clicking "Submit Application" you consent to Klaviyo processing your Personal Data in accordance with our Job Applicant Privacy Notice. If you do not wish for Klaviyo to process your Personal Data, please do not submit an application. You can find our Job Applicant Privacy Notice here and here (FR).

At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you're a close but not exact match with the description, we hope you'll still consider applying. Want to learn more about life at Klaviyo? Visit careers.klaviyo.com to see how we empower creators to own their own destiny. Location: Boston Hybrid (3 days/week in office) Lead Software Engineer - Campaigns Configuration At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you're a close but not exact match with the description, we hope you'll still consider applying. Want to learn more about life at Klaviyo? Visit careers.klaviyo.com to see how we empower creators to own their own destiny. Why You Should Join the Campaigns Configuration Team The Campaigns Configuration team is building the foundation for how Klaviyo customers create, manage, schedule, and understand the performance of their marketing campaigns across channels. This team owns the core configuration and reporting experiences that power Klaviyo's Campaigns product. Campaigns are one of the most used parts of the Klaviyo application, relied on by hundreds of thousands of customers to send targeted messages (Email, SMS, Push Notifications, and more) that deepen their relationships with their own customers. By joining the Campaigns Configuration team, you will have a direct impact on over 170,000 brands that use Klaviyo every day. The team owns an ambitious roadmap, including: A reimagined Campaigns experience built from the ground up A new Omnichannel Campaign experience allowing users to send campaigns on multiple channels Intelligent personalization and future channel expansion Refactoring Klaviyo's system architecture through domain decomposition Re-architecting the Campaigns experience for performance, scalability, and reliability As a Lead Software Engineer on this team, you'll sit at the intersection of architecture, execution, and cross-team collaboration for one of Klaviyo's flagship product areas. About the Role As a Lead Software Engineer, you are the technical leader and primary interface between the Campaigns Configuration team and the broader engineering organization. You will: Provide technical oversight and direction across a portfolio of projects Shape and execute on the forward-looking architecture for multiple Campaigns domains Partner closely with the Engineering Manager, Product, and Design on strategy, planning, and execution Work through influence and delegation to help the team deliver reliably and at a high bar of quality You'll spend your time balancing hands-on work (design docs, reviews, complex implementation) with guiding the team toward solid technical decisions, especially at our largest scales (including Black Friday / Cyber Monday, when we help customers send billions of messages). How You Will Make a Difference Lead technical direction for Campaigns Configuration Provide technical oversight and direction for a portfolio of Campaigns projects, including new channels, personalization, and analytics. Formulate and drive a forward-looking technical vision that aligns with broader business and platform initiatives. Own architecture and domain evolution Be responsible for the technical and architectural evolution of multiple key Campaigns domains (e.g., configuration, scheduling, reporting). Drive domain decomposition, service boundaries, and data model design to improve scalability, performance, and operational excellence. Deliver high-quality, scalable features Lead the design and implementation of best-in-class web experiences using React and TypeScript, backed by REST and GraphQL APIs. Ensure backend systems are robust, observable, and performant, with an eye on peak traffic events. Scrutinize and reduce technical ambiguity and risk for upcoming projects through design reviews, technical spikes, and clear decision records. Create and improve engineering processes Work with the Engineering Manager to ensure team adherence to solid engineering practices (testing, observability, rollout strategies, incident response). Create, teach, and improve shared engineering processes and patterns that can be adopted by adjacent teams. Uplevel adjacent processes, technology, and people by sharing best practices and reusable solutions. Influence beyond your immediate team Act as the primary technical interface to other Campaigns and platform teams, ensuring cohesive end-to-end solutions. Regularly collaborate with technical leads in other areas to align on patterns, standards, and shared components. Mentor and grow others Guide other engineers through design feedback, pairing, and thoughtful code reviews. Help teammates break down complex initiatives into clear, incremental deliverables with predictable timelines. Who You Are 7+ years of software engineering experience, including significant fullstack work Strong backend experience, with a track record of building and scaling services in production Hands-on experience with: Frontend: React, TypeScript, and modern state management patterns (e.g., Redux or equivalent) Backend: Python with Django, FastAPI (or equivalent web frameworks), Go APIs: RESTful and GraphQL APIs Data & performance: relational databases (e.g., MySQL/Postgres), query optimization, caching, and performance tuning Experience acting as a tech lead or lead engineer for a team or domain: You have driven technical vision and execution for a portfolio of projects. You've owned architecture in at least one significant product area. You're comfortable saying “no” or “not yet” when it protects long-term health. Strong systems and product thinking: Skilled in system design, reusable component architecture, and scalable frontend platforms. Comfortable designing systems that operate reliably at large scale and high traffic. Able to translate product ideas into pragmatic, incremental technical plans. Collaborative and influential: You work through influence and delegation rather than just personal heroics. You communicate clearly with engineers, product managers, and designers. You proactively provide and receive feedback within your pillar and across teams. Growth-oriented: Proven track record delivering complex features in fast-paced, product-led environments. You've experimented with AI tools in work or personal projects, and you're eager to learn how they can improve developer and customer experiences. Experience with marketing automation, messaging platforms, or analytics-heavy products is a plus, but not required. Technologies We Use You don't need to know all of these on day one, but familiarity with several is helpful: Frontend: React, TypeScript, Redux Backend: Python, Django, FastAPI, Go Data & messaging: MySQL, Redis, RabbitMQ, Pulsar APIs: GraphQL, REST Infrastructure: AWS, Terraform, Kubernetes We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025. Please see the independent bias audit report covering our use of Covey here Massachusetts Applicants: It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability. Our salary range reflects the cost of labor across various U.S. geographic markets. The range displayed below reflects the minimum and maximum target salaries for the position across all our US locations. The base salary offered for this position is determined by several factors, including the applicant's job-related skills, relevant experience, education or training, and work location. In addition to base salary, our total compensation package may include participation in the company's annual cash bonus plan, variable compensation (OTE) for sales and customer success roles, equity, sign-on payments, and a comprehensive range of health, welfare, and wellbeing benefits based on eligibility. Your recruiter can provide more details about the specific salary/OTE range for your preferred location during the hiring process. Base Pay Range For US Locations:$188,000-$282,000 USD Get to Know Klaviyo We're Klaviyo (pronounced clay-vee-oh). We empower creators to own their destiny by making first-party data accessible and actionable like never before. We see limitless potential for the technology we're developing to nurture personalized experiences in ecommerce and beyond. To reach our goals, we need our own crew of remarkable creators-ambitious and collaborative teammates who stay focused on our north star: delighting our customers. If you're ready to do the best work of your career, where you'll be welcomed as your whole self from day one and supported with generous benefits, we hope you'll join us. AI fluency at Klaviyo includes responsible use of AI (including privacy, security, bias awareness, and human-in-the-loop). We provide accommodations as needed. By participating in Klaviyo's interview process, you acknowledge that you have read, understood, and will adhere to our Guidelines for using AI in the Klaviyo interview Process. For more information about how we process your personal data, see our Job Applicant Privacy Notice. Klaviyo is committed to a policy of equal opportunity and non-discrimination. We do not discriminate on the basis of race, ethnicity, citizenship, national origin, color, religion or religious creed, age, sex (including pregnancy), gender identity, sexual orientation, physical or mental disability, veteran or active military status, marital status, criminal record, genetics, retaliation, sexual harassment or any other characteristic protected by applicable law. IMPORTANT NOTICE: Our company takes the security and privacy of job applicants very seriously. We will never ask for payment, bank details, or personal financial information as part of the application process. All our legitimate job postings can be found on our official career site. Please be cautious of job offers that come from non-company email addresses (@klaviyo.com), instant messaging platforms, or unsolicited calls. By clicking "Submit Application" you consent to Klaviyo processing your Personal Data in accordance with our Job Applicant Privacy Notice. If you do not wish for Klaviyo to process your Personal Data, please do not submit an application. You can find our Job Applicant Privacy Notice here and here (FR).

At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you're a close but not exact match with the description, we hope you'll still consider applying. Want to learn more about life at Klaviyo? Visit careers.klaviyo.com to see how we empower creators to own their own destiny. Why You Should Join the Billing Team: The Billing team at Klaviyo is at the heart of how we deliver value to our customers and drive revenue for the business. We're responsible for everything from pricing and payments to product entitlements. Our systems ensure customers are billed accurately and have access to the features they've selected. As Klaviyo expands globally and launches new product offerings, our team plays a pivotal role in enabling speed, flexibility, and scale across the company. As an Lead Software Engineer on this team, you'll lead a group of engineers focused on building internal platforms that empower teams across Klaviyo to self-serve product packaging, entitlements, and billing logic. You'll oversee work to build a pricing and packaging platform, and to build scalable infrastructure that supports international growth. This is a hands-on leadership role where you'll contribute to code, design, and strategy. Your work will directly enable faster product launches, better customer experiences, and improved business outcomes. How You Will Make a Difference: Lead a team of engineers building a new internal pricing and billing platform Own Klaviyo's 3rd party payment and billing integrations and expand payment capabilities Build scalable systems to support international markets and payment flexibility Contribute directly to architecture and code, driving best practices and quality Collaborate with cross-functional teams to unlock product revenue opportunities Grow and mentor engineers while helping shape the future of billing at Klaviyo Transform workflows by putting AI at the center, building smarter systems and ways of working from the ground up. Who You Are: 8+ years of engineering experience with strong backend skills (Python or similar) Comfortable coding and reviewing complex systems - this is a hands-on role Experience with fullstack development (React familiarity is a plus) Proven experience with third-party APIs, especially Stripe or payment systems Skilled in system design and scaling infrastructure using AWS Experience building developer platforms or internal tooling is a strong plus Clear communicator and collaborative team player You've already experimented with AI in work or personal projects, and you're excited to dive in and learn fast. You're hungry to responsibly explore new AI tools and workflows, finding ways to make your work smarter and more efficient. Technologies We Use: Python, Django React, TypeScript Stripe API, RESTful integrations AWS, Terraform, Redis, MySQL Location: This is a hybrid role based in Boston, with 3 days in office and 2 days remote per week. We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025. Please see the independent bias audit report covering our use of Covey here Massachusetts Applicants: It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability. Our salary range reflects the cost of labor across various U.S. geographic markets. The range displayed below reflects the minimum and maximum target salaries for the position across all our US locations. The base salary offered for this position is determined by several factors, including the applicant's job-related skills, relevant experience, education or training, and work location. In addition to base salary, our total compensation package may include participation in the company's annual cash bonus plan, variable compensation (OTE) for sales and customer success roles, equity, sign-on payments, and a comprehensive range of health, welfare, and wellbeing benefits based on eligibility. Your recruiter can provide more details about the specific salary/OTE range for your preferred location during the hiring process. Base Pay Range For US Locations:$188,000-$282,000 USD Get to Know Klaviyo We're Klaviyo (pronounced clay-vee-oh). We empower creators to own their destiny by making first-party data accessible and actionable like never before. We see limitless potential for the technology we're developing to nurture personalized experiences in ecommerce and beyond. To reach our goals, we need our own crew of remarkable creators-ambitious and collaborative teammates who stay focused on our north star: delighting our customers. If you're ready to do the best work of your career, where you'll be welcomed as your whole self from day one and supported with generous benefits, we hope you'll join us. AI fluency at Klaviyo includes responsible use of AI (including privacy, security, bias awareness, and human-in-the-loop). We provide accommodations as needed. By participating in Klaviyo's interview process, you acknowledge that you have read, understood, and will adhere to our Guidelines for using AI in the Klaviyo interview Process. For more information about how we process your personal data, see our Job Applicant Privacy Notice. Klaviyo is committed to a policy of equal opportunity and non-discrimination. We do not discriminate on the basis of race, ethnicity, citizenship, national origin, color, religion or religious creed, age, sex (including pregnancy), gender identity, sexual orientation, physical or mental disability, veteran or active military status, marital status, criminal record, genetics, retaliation, sexual harassment or any other characteristic protected by applicable law. IMPORTANT NOTICE: Our company takes the security and privacy of job applicants very seriously. We will never ask for payment, bank details, or personal financial information as part of the application process. All our legitimate job postings can be found on our official career site. Please be cautious of job offers that come from non-company email addresses (@klaviyo.com), instant messaging platforms, or unsolicited calls. By clicking "Submit Application" you consent to Klaviyo processing your Personal Data in accordance with our Job Applicant Privacy Notice. If you do not wish for Klaviyo to process your Personal Data, please do not submit an application. You can find our Job Applicant Privacy Notice here and here (FR).

At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you're a close but not exact match with the description, we hope you'll still consider applying. Want to learn more about life at Klaviyo? Visit careers.klaviyo.com to see how we empower creators to own their own destiny. Lead AI Engineer At Klaviyo, we believe the future of software lies not in productivity tools for human users but in systems that can learn, run, and optimize themselves based on measurable outcomes. We've built the infrastructure and applications that power the interface between businesses and consumers - supporting over 167,000 customers, billions of consumer profiles, and hundreds of billions of customer interactions. Now, we're building the next generation of AI and machine learning technologies to power these products - enabling AI agents that can automatically create, execute, and optimize marketing and customer experience strategies for any business. As a Lead AI Engineer, you'll take ownership of designing, building, and scaling the backend and machine learning systems that form the foundation of Klaviyo's AI strategy. You'll partner closely with product managers, data scientists, and engineers to deliver intelligent, outcome-driven systems that operate at massive scale - while mentoring others and setting technical direction for the team. How You Will Make a Difference Lead the design and development of backend and ML systems that scale to serve 167K+ customers. Build robust, reliable, and efficient data processing and model-serving pipelines that power production ML models. Develop and optimize predictive systems (e.g., conversion likelihood, engagement ranking, personalization, anomaly detection). Architect systems and services that enable our AI agents to learn and improve autonomously from reward or outcome signals. Collaborate cross-functionally to translate business challenges into scalable, measurable ML solutions. Collaborate with software engineers and product managers to turn predictive models into intuitive product features for our customers. Mentor engineers and help evolve Klaviyo's ML engineering best practices, tooling, and architecture. Foster a culture of ownership, experimentation, and data-driven innovation across teams. Who You Are 7-10 years of experience in machine learning engineering or applied software engineering, with a focus on classical ML and predictive modeling. Deep understanding of supervised learning methods such as random forests, XGBoost, logistic regression, and ensemble techniques. Proven track record of building and scaling production-grade ML systems end to end (data pipelines, training, deployment, and monitoring). Experienced backend engineer comfortable with distributed systems and high-scale architectures. Proficient in Python and modern frameworks (FastAPI, Django preferred). Skilled with big data and streaming technologies (Apache Spark, Kafka, Hadoop). Hands-on with asynchronous processing and distributed task queues (Celery, SQS, RabbitMQ, Redis). Strong understanding of databases and ORMs (SQLAlchemy, Alembic) and cloud-native architectures (AWS, Kubernetes, CI/CD). Excellent communicator who can set technical direction, influence product strategy, and mentor junior engineers. Curious, pragmatic, and passionate about building AI systems that drive measurable business impact. Nice to Have Experience training and deploying ML models in production environments that generated measurable impact. Familiarity with reinforcement learning or agentic AI systems that adapt based on outcome or reward signals. We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025. Please see the independent bias audit report covering our use of Covey here Massachusetts Applicants: It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability. Our salary range reflects the cost of labor across various U.S. geographic markets. The range displayed below reflects the minimum and maximum target salaries for the position across all our US locations. The base salary offered for this position is determined by several factors, including the applicant's job-related skills, relevant experience, education or training, and work location. In addition to base salary, our total compensation package may include participation in the company's annual cash bonus plan, variable compensation (OTE) for sales and customer success roles, equity, sign-on payments, and a comprehensive range of health, welfare, and wellbeing benefits based on eligibility. Your recruiter can provide more details about the specific salary/OTE range for your preferred location during the hiring process. Base Pay Range For US Locations:$188,000-$282,000 USD Get to Know Klaviyo We're Klaviyo (pronounced clay-vee-oh). We empower creators to own their destiny by making first-party data accessible and actionable like never before. We see limitless potential for the technology we're developing to nurture personalized experiences in ecommerce and beyond. To reach our goals, we need our own crew of remarkable creators-ambitious and collaborative teammates who stay focused on our north star: delighting our customers. If you're ready to do the best work of your career, where you'll be welcomed as your whole self from day one and supported with generous benefits, we hope you'll join us. AI fluency at Klaviyo includes responsible use of AI (including privacy, security, bias awareness, and human-in-the-loop). We provide accommodations as needed. By participating in Klaviyo's interview process, you acknowledge that you have read, understood, and will adhere to our Guidelines for using AI in the Klaviyo interview Process. For more information about how we process your personal data, see our Job Applicant Privacy Notice. Klaviyo is committed to a policy of equal opportunity and non-discrimination. We do not discriminate on the basis of race, ethnicity, citizenship, national origin, color, religion or religious creed, age, sex (including pregnancy), gender identity, sexual orientation, physical or mental disability, veteran or active military status, marital status, criminal record, genetics, retaliation, sexual harassment or any other characteristic protected by applicable law. IMPORTANT NOTICE: Our company takes the security and privacy of job applicants very seriously. We will never ask for payment, bank details, or personal financial information as part of the application process. All our legitimate job postings can be found on our official career site. Please be cautious of job offers that come from non-company email addresses (@klaviyo.com), instant messaging platforms, or unsolicited calls. By clicking "Submit Application" you consent to Klaviyo processing your Personal Data in accordance with our Job Applicant Privacy Notice. If you do not wish for Klaviyo to process your Personal Data, please do not submit an application. You can find our Job Applicant Privacy Notice here and here (FR).

At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you're a close but not exact match with the description, we hope you'll still consider applying. Want to learn more about life at Klaviyo? Visit careers.klaviyo.com to see how we empower creators to own their own destiny. Lead Site Reliability Engineering (SRE) is what you get when you treat system operations as a software engineering problem. The mission of the Site Reliability Engineering team is to ensure uninterrupted service for Klaviyo customers and act as a force multiplier for Klaviyo product teams to deliver better software faster. The SRE team builds foundational backend services as well as tooling and automation to allow product teams to release and scale their software reliably and predictably. Lead SREs are team players who embed themselves within product teams as needed to advance the architecture and performance of software systems and train their peers in topics such as debugging distributed systems, building self-healing applications and eking out every drop of performance possible. As a Lead Site Reliability Engineer, you will own the ways we solve problems for our customers, and make a big impact on the productivity of our product engineering teams. Klaviyo is growing fast and we have openings for all skill levels across all of our teams. Learn more about our engineering culture at ******************** How You'll Make a Difference Ship foundational services to enable Klaviyo engineering to move faster with confidence Design and develop systems and processes that enable highly available & scalable systems Uncover and advocate for preventative, upstream solutions with internal stakeholders Own the technical vision and roadmap for your area, working with stakeholders to solve pain points and deliver value to engineering Achieve break-throughs in systems throughput by identifying and eliminating bottlenecks Leverage technology such as Python, AWS, Django, Kubernetes, Bash, Terraform, MySQL, Redis, Postgresql to advance Klaviyo's platform Champion best practices by actively collaborating with other teams in a culture that values whiteboarding and technical design review Contribute to the company in multiple areas, constantly pushing yourself to be a better engineer and to level up all of your peers within your team and within Klaviyo. Design, write and deliver software to dramatically improve the availability, scalability, latency, and efficiency of Klaviyo's services Participate in periodic on call duties with a focus on solving issues when they are discovered, preventing recurrences and minimizing alert fatigue Implement architectural improvements to achieve breakthrough results in Klaviyo systems' operational scalability and reliability. Work hand-in-hand with product-facing engineers and other SREs to ship impactful code Perform quantitative analysis to understand and scale Klaviyo systems Evangelize Site Reliability best practices across the engineering organization Who You Are Solid 10+ years of experience in the SRE/Devops field BA or BS Degree in Computer Science, related field, or equivalent experience Ability to handle yourself in outage situations and to drive failures to root cause analysis and prevention of future issues Understanding of Linux (we run Ubuntu) and all layers of the networking stack Experience working on an engineering team building software Experience writing code using best practices in a language such as Python, Ruby, Go, etc. You've already experimented with AI in work or personal projects, and you're excited to dive in and learn fast. You're hungry to responsibly explore new AI tools and workflows, finding ways to make your work smarter and more efficient. We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025. Please see the independent bias audit report covering our use of Covey here Massachusetts Applicants: It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability. Our salary range reflects the cost of labor across various U.S. geographic markets. The range displayed below reflects the minimum and maximum target salaries for the position across all our US locations. The base salary offered for this position is determined by several factors, including the applicant's job-related skills, relevant experience, education or training, and work location. In addition to base salary, our total compensation package may include participation in the company's annual cash bonus plan, variable compensation (OTE) for sales and customer success roles, equity, sign-on payments, and a comprehensive range of health, welfare, and wellbeing benefits based on eligibility. Your recruiter can provide more details about the specific salary/OTE range for your preferred location during the hiring process. Base Pay Range For US Locations:$188,000-$282,000 USD Get to Know Klaviyo We're Klaviyo (pronounced clay-vee-oh). We empower creators to own their destiny by making first-party data accessible and actionable like never before. We see limitless potential for the technology we're developing to nurture personalized experiences in ecommerce and beyond. To reach our goals, we need our own crew of remarkable creators-ambitious and collaborative teammates who stay focused on our north star: delighting our customers. If you're ready to do the best work of your career, where you'll be welcomed as your whole self from day one and supported with generous benefits, we hope you'll join us. AI fluency at Klaviyo includes responsible use of AI (including privacy, security, bias awareness, and human-in-the-loop). We provide accommodations as needed. By participating in Klaviyo's interview process, you acknowledge that you have read, understood, and will adhere to our Guidelines for using AI in the Klaviyo interview Process. For more information about how we process your personal data, see our Job Applicant Privacy Notice. Klaviyo is committed to a policy of equal opportunity and non-discrimination. We do not discriminate on the basis of race, ethnicity, citizenship, national origin, color, religion or religious creed, age, sex (including pregnancy), gender identity, sexual orientation, physical or mental disability, veteran or active military status, marital status, criminal record, genetics, retaliation, sexual harassment or any other characteristic protected by applicable law. IMPORTANT NOTICE: Our company takes the security and privacy of job applicants very seriously. We will never ask for payment, bank details, or personal financial information as part of the application process. All our legitimate job postings can be found on our official career site. Please be cautious of job offers that come from non-company email addresses (@klaviyo.com), instant messaging platforms, or unsolicited calls. By clicking "Submit Application" you consent to Klaviyo processing your Personal Data in accordance with our Job Applicant Privacy Notice. If you do not wish for Klaviyo to process your Personal Data, please do not submit an application. You can find our Job Applicant Privacy Notice here and here (FR).

At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you're a close but not exact match with the description, we hope you'll still consider applying. Want to learn more about life at Klaviyo? Visit careers.klaviyo.com to see how we empower creators to own their own destiny. Why You Should Join the Email Platforms Team: The Email Platforms team at Klaviyo is building the next generation of infrastructure to support reliable, scalable, and performant email delivery. Our mission is to help Klaviyo reach enterprise scale by evolving and owning our email sending pipeline end-to-end. We're investing heavily in our homegrown email delivery infrastructure, giving us greater control, performance, and reliability in how we deliver emails for some of the largest brands in the world. As a Lead Software Engineer on this team, you'll lead a group of engineers focused on designing and scaling high-throughput email delivery systems. You'll drive the architecture of our messaging infrastructure, own critical components of the email pipeline, and help shape the technical direction of the team. This is a hands-on role where you'll contribute to code, design, and lead strategy. Your work will directly impact customer satisfaction, deliverability, and business success as we bring on larger enterprise accounts. How You Will Make a Difference: Lead a team of engineers building and scaling Klaviyo's email delivery infrastructure Own and drive the architecture of key components in the email pipeline Design and implement scalable, high-throughput services in Go and Python Build systems that manage message queues and ensure reliable email delivery at scale Contribute directly to architecture and code, driving best practices and quality Collaborate cross-functionally to ensure the highest standards of performance, reliability, and deliverability Grow and mentor engineers while helping shape the future of email infrastructure at Klaviyo Transform workflows by putting AI at the center, building smarter systems and ways of working from the ground up Who You Are: 8+ years of engineering experience with strong backend and systems design skills Proficient in Go and Python (required) Comfortable coding and reviewing complex systems - this is a hands-on role Experienced working with high-throughput distributed systems Familiar with message queues (e.g., Pulsar, Kafka, RabbitMQ, SQS) Skilled in system design and scaling infrastructure using AWS Bonus: Experience with email infrastructure, MTAs, deliverability, or mailops Clear communicator and collaborative team player Able to thrive in a hybrid team(with some remote team members) and deliver in a high-autonomy environment You've already experimented with AI in work or personal projects, and you're excited to dive in and learn fast. You're hungry to responsibly explore new AI tools and workflows, finding ways to make your work smarter and more efficient. We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025. Please see the independent bias audit report covering our use of Covey here Massachusetts Applicants: It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability. Our salary range reflects the cost of labor across various U.S. geographic markets. The range displayed below reflects the minimum and maximum target salaries for the position across all our US locations. The base salary offered for this position is determined by several factors, including the applicant's job-related skills, relevant experience, education or training, and work location. In addition to base salary, our total compensation package may include participation in the company's annual cash bonus plan, variable compensation (OTE) for sales and customer success roles, equity, sign-on payments, and a comprehensive range of health, welfare, and wellbeing benefits based on eligibility. Your recruiter can provide more details about the specific salary/OTE range for your preferred location during the hiring process. Base Pay Range For US Locations:$188,000-$282,000 USD Get to Know Klaviyo We're Klaviyo (pronounced clay-vee-oh). We empower creators to own their destiny by making first-party data accessible and actionable like never before. We see limitless potential for the technology we're developing to nurture personalized experiences in ecommerce and beyond. To reach our goals, we need our own crew of remarkable creators-ambitious and collaborative teammates who stay focused on our north star: delighting our customers. If you're ready to do the best work of your career, where you'll be welcomed as your whole self from day one and supported with generous benefits, we hope you'll join us. AI fluency at Klaviyo includes responsible use of AI (including privacy, security, bias awareness, and human-in-the-loop). We provide accommodations as needed. By participating in Klaviyo's interview process, you acknowledge that you have read, understood, and will adhere to our Guidelines for using AI in the Klaviyo interview Process. For more information about how we process your personal data, see our Job Applicant Privacy Notice. Klaviyo is committed to a policy of equal opportunity and non-discrimination. We do not discriminate on the basis of race, ethnicity, citizenship, national origin, color, religion or religious creed, age, sex (including pregnancy), gender identity, sexual orientation, physical or mental disability, veteran or active military status, marital status, criminal record, genetics, retaliation, sexual harassment or any other characteristic protected by applicable law. IMPORTANT NOTICE: Our company takes the security and privacy of job applicants very seriously. We will never ask for payment, bank details, or personal financial information as part of the application process. All our legitimate job postings can be found on our official career site. Please be cautious of job offers that come from non-company email addresses (@klaviyo.com), instant messaging platforms, or unsolicited calls. By clicking "Submit Application" you consent to Klaviyo processing your Personal Data in accordance with our Job Applicant Privacy Notice. If you do not wish for Klaviyo to process your Personal Data, please do not submit an application. You can find our Job Applicant Privacy Notice here and here (FR).

At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you're a close but not exact match with the description, we hope you'll still consider applying. Want to learn more about life at Klaviyo? Visit careers.klaviyo.com to see how we empower creators to own their own destiny. Klaviyo is growing fast and we have openings for all skill levels across all of our teams. Learn more about our engineering culture at ******************** We love tackling tough engineering problems and look for Engineers who specialize in certain areas but are passionate about building, owning & scaling features end to end from scratch and breaking through any obstacle or technical challenge in their way. We push each other to move out of our comfort zone, learn new technologies and work hard to ensure each day is better than the last. Klaviyo operates a real-time data platform coded in Python built for massive scale on Amazon Web Services (AWS). Engineers come to Klaviyo with experience in a variety of languages and from a number of disciplines. Team Overview: DevX is a hybrid product-platform team focused on empowering external developers and partners by supporting applications they build on top of Klaviyo's Public APIs and features. Examples of these areas of ownership include: our Application directory, which is used to promote and allow Klaviyo customers to discover applications that they can enable for their account the self-serve application process for a Partner to submit an Application and the ability for Klaviyo staff to review and approve an Application API Analytics is a system used by developers and partners to diagnose issues in their applications and understand their API usage. It is powered by a near real-time data pipeline that processes over 160,000 events per second. Autogenerated API docs, SDKs, CLIs & MCP servers Responsibilities: You will have an opportunity to make a major impact on the direction and priorities of the team. As an engineer on this team, you will work on Klaviyo's app marketplace, application publishing workflows, and the developer-facing tools and systems that support our app ecosystem. Additional responsibilities include providing quality PR reviews for our code-owned areas of the application, collaborating with product owners and providing technical expertise on upcoming Product Specifications, and participating in the definition of well-defined, estimated, and planned scopes of work. Required Skills: 3-5+ years of experience in a software engineering discipline Experience with full stack application development Experience working with both monolithic and microservices architectures Experience with CI/CD pipelines Experience debugging performance issues and improving application performance Team Tech Stack: Python Django REST Framework, Django, fast API React, React Query MySQL / postgre SQL DocumentDB Clickhouse JSON Forms Redis Memcached RabbitMQ / Celery / Apache Pulsar Preferred Skills: Experience working with Service Oriented Architecture (preferably in Python) Experience working with RESTful applications/APIs/gRPC We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025. Please see the independent bias audit report covering our use of Covey here Massachusetts Applicants: It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability. Our salary range reflects the cost of labor across various U.S. geographic markets. The range displayed below reflects the minimum and maximum target salaries for the position across all our US locations. The base salary offered for this position is determined by several factors, including the applicant's job-related skills, relevant experience, education or training, and work location. In addition to base salary, our total compensation package may include participation in the company's annual cash bonus plan, variable compensation (OTE) for sales and customer success roles, equity, sign-on payments, and a comprehensive range of health, welfare, and wellbeing benefits based on eligibility. Your recruiter can provide more details about the specific salary/OTE range for your preferred location during the hiring process. Base Pay Range For US Locations:$120,000-$180,000 USD Get to Know Klaviyo We're Klaviyo (pronounced clay-vee-oh). We empower creators to own their destiny by making first-party data accessible and actionable like never before. We see limitless potential for the technology we're developing to nurture personalized experiences in ecommerce and beyond. To reach our goals, we need our own crew of remarkable creators-ambitious and collaborative teammates who stay focused on our north star: delighting our customers. If you're ready to do the best work of your career, where you'll be welcomed as your whole self from day one and supported with generous benefits, we hope you'll join us. AI fluency at Klaviyo includes responsible use of AI (including privacy, security, bias awareness, and human-in-the-loop). We provide accommodations as needed. By participating in Klaviyo's interview process, you acknowledge that you have read, understood, and will adhere to our Guidelines for using AI in the Klaviyo interview Process. For more information about how we process your personal data, see our Job Applicant Privacy Notice. Klaviyo is committed to a policy of equal opportunity and non-discrimination. We do not discriminate on the basis of race, ethnicity, citizenship, national origin, color, religion or religious creed, age, sex (including pregnancy), gender identity, sexual orientation, physical or mental disability, veteran or active military status, marital status, criminal record, genetics, retaliation, sexual harassment or any other characteristic protected by applicable law. IMPORTANT NOTICE: Our company takes the security and privacy of job applicants very seriously. We will never ask for payment, bank details, or personal financial information as part of the application process. All our legitimate job postings can be found on our official career site. Please be cautious of job offers that come from non-company email addresses (@klaviyo.com), instant messaging platforms, or unsolicited calls. By clicking "Submit Application" you consent to Klaviyo processing your Personal Data in accordance with our Job Applicant Privacy Notice. If you do not wish for Klaviyo to process your Personal Data, please do not submit an application. You can find our Job Applicant Privacy Notice here and here (FR).

At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you're a close but not exact match with the description, we hope you'll still consider applying. Want to learn more about life at Klaviyo? Visit careers.klaviyo.com to see how we empower creators to own their own destiny. As the Software Engineer, Product Recommendations at Klaviyo, you'll help build the machine learning-powered systems that decide which products to show to whom and when across our platform. You'll work on large-scale backend and data systems that turn billions of behavioral events into real-time, personalized product recommendations that drive revenue for merchants of all sizes. You'll join the Product Recommendation team, partnering closely with Machine Learning Engineers, AI Engineers, other engineers, Product Managers and Designers to design, build, and operate services and data pipelines that power our recommendation features end to end-from data ingestion and feature generation to ranking models and APIs exposed in product. This is a hands-on backend role with a strong focus on building scalable systems and data processing frameworks, with prior ML system experience as a plus (not a hard requirement). How you'll make a difference Design, build, and operate backend services that power product recommendations across Klaviyo experiences (email, SMS, KAgent, onsite, etc.), with a focus on reliability, performance, and clear APIs. Build and maintain large-scale data processing pipelines (e.g., using Apache Spark or similar frameworks) that transform raw events and catalog data into high-quality features and inputs for recommendation models. Collaborate with ML engineers to productionize recommendation models-defining interfaces, feature contracts, and deployment patterns for batch and/or real-time inference. Build ML/AI systems such as vector search that power recommendation, semantic search, and agentic use cases. Implement and evolve data and service observability (metrics, logging, tracing, dashboards) to ensure recommendations are correct, fast, and available when customers need them. Contribute to and improve shared data frameworks, libraries, and patterns that make it easier to build new recommendation use cases and iterate quickly. Work with product managers to break down complex recommendation initiatives into clear milestones, helping balance experimentation speed with reliability and technical soundness. Partner on data-driven decision making and A/B testing-ensuring recommendation systems are instrumented with the right metrics, and helping interpret results to guide future iterations. Participate in on-call and incident response for the systems you own, driving follow-ups that improve the resilience and operability of our recommendation stack. Transform workflows by putting AI at the center, building smarter systems and ways of working from the ground up-for example, using AI to accelerate development, automate tests, or better monitor and debug recommendation behavior. Share knowledge and mentor other engineers on working with large-scale data frameworks, distributed systems, and best practices for integrating ML into production systems. Who you are 3+ years of software engineering experience, including building and operating backend services in production. Strong focus on backend and distributed systems at scale; you've worked on high-throughput or highly available services and care about latency, reliability, and operability. Proficient in Python, and comfortable working in at least one modern language used for backend/data work (e.g., Java or Scala). Proficient with big data frameworks such as Apache Spark (or similar technologies like Flink, Beam, etc.) for building batch or streaming pipelines. Comfortable with cloud-native architectures (AWS preferred) and container orchestration (e.g., Kubernetes); able to work with infrastructure and CI/CD pipelines as part of your day-to-day development. Comfortable with data-driven decision making and A/B testing-you understand how to instrument experiments, read results, and fold learnings back into the system. Comfortable designing and querying data models in relational or analytical datastores (e.g., Postgres, MySQL, data warehouses). Familiarity with modern DevOps practices (CI/CD, monitoring, alerting) and how they apply to large-scale data and recommendation systems. Proven track record of owning projects end-to-end-from design and implementation through rollout, monitoring, and iteration-ideally across multiple components or services. Excellent collaborator and communicator: you can explain tradeoffs to technical and non-technical partners and work effectively with ML Engineers, Software Engineers, PMs, and other teams. You've already experimented with AI in work or personal projects, and you're excited to dive in and learn fast. You're hungry to responsibly explore new AI tools and workflows, finding ways to make your work smarter and more efficient. Nice to haves Previous experience working on product recommendation systems or adjacent ML-powered features (ranking, personalization, search, or similar). Experience in AI/ML systems and products, such as integrating models into production systems or building features powered by ML. Experience training machine learning models (e.g., for ranking, prediction, or personalization), even if you don't consider yourself a full-time ML engineer. Experience with ML and distributed compute frameworks such as Ray or similar tools. Experience partnering with data science or ML teams to productionize models (feature stores, offline/online parity, model deployment and monitoring). Experience with additional data technologies (e.g., Kafka, Kinesis, Redis, feature stores, or vector databases). Background in e-commerce, marketing tech, or consumer personalization products We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025. Please see the independent bias audit report covering our use of Covey here Massachusetts Applicants: It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability. Our salary range reflects the cost of labor across various U.S. geographic markets. The range displayed below reflects the minimum and maximum target salaries for the position across all our US locations. The base salary offered for this position is determined by several factors, including the applicant's job-related skills, relevant experience, education or training, and work location. In addition to base salary, our total compensation package may include participation in the company's annual cash bonus plan, variable compensation (OTE) for sales and customer success roles, equity, sign-on payments, and a comprehensive range of health, welfare, and wellbeing benefits based on eligibility. Your recruiter can provide more details about the specific salary/OTE range for your preferred location during the hiring process. Base Pay Range For US Locations:$120,000-$180,000 USD Get to Know Klaviyo We're Klaviyo (pronounced clay-vee-oh). We empower creators to own their destiny by making first-party data accessible and actionable like never before. We see limitless potential for the technology we're developing to nurture personalized experiences in ecommerce and beyond. To reach our goals, we need our own crew of remarkable creators-ambitious and collaborative teammates who stay focused on our north star: delighting our customers. If you're ready to do the best work of your career, where you'll be welcomed as your whole self from day one and supported with generous benefits, we hope you'll join us. AI fluency at Klaviyo includes responsible use of AI (including privacy, security, bias awareness, and human-in-the-loop). We provide accommodations as needed. By participating in Klaviyo's interview process, you acknowledge that you have read, understood, and will adhere to our Guidelines for using AI in the Klaviyo interview Process. For more information about how we process your personal data, see our Job Applicant Privacy Notice. Klaviyo is committed to a policy of equal opportunity and non-discrimination. We do not discriminate on the basis of race, ethnicity, citizenship, national origin, color, religion or religious creed, age, sex (including pregnancy), gender identity, sexual orientation, physical or mental disability, veteran or active military status, marital status, criminal record, genetics, retaliation, sexual harassment or any other characteristic protected by applicable law. IMPORTANT NOTICE: Our company takes the security and privacy of job applicants very seriously. We will never ask for payment, bank details, or personal financial information as part of the application process. All our legitimate job postings can be found on our official career site. Please be cautious of job offers that come from non-company email addresses (@klaviyo.com), instant messaging platforms, or unsolicited calls. By clicking "Submit Application" you consent to Klaviyo processing your Personal Data in accordance with our Job Applicant Privacy Notice. If you do not wish for Klaviyo to process your Personal Data, please do not submit an application. You can find our Job Applicant Privacy Notice here and here (FR).

At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you're a close but not exact match with the description, we hope you'll still consider applying. Want to learn more about life at Klaviyo? Visit careers.klaviyo.com to see how we empower creators to own their own destiny. Why You Should Join the Editors Team: The Editors team is responsible for building common reusable components for the message editor. This team powers all the editors at Klaviyo. This team focuses on building intuitive and powerful interfaces to create highly customizable and dynamic content ranging from product feeds, real time event data, and more. This product area is core to Klaviyo's continued success. As a Software Engineer II on the team, you'll play a key role in designing and building scalable systems that power our editor experiences across all the editors. Partnering closely with product managers and technical product owners, you'll help define scope, translate ideas into practical implementations, and build intuitive editing tools that delight our users. This role leans frontend, with a strong focus on crafting thoughtful, reusable components and seamless user experiences using technologies like TypeScript, React, Python, and Django. There are ample opportunities for growth given the scope of this role and the team's central role in Klaviyo's product. Over the past year, our team has enhanced the editor interfaces with impactful features that our customers love-and they're eager to see that same power brought to other mobile experiences. Looking ahead, we'll be investing in new editor blocks, a personalization builder, in-canvas editing, and content generation powered by AI. You'll contribute directly to these efforts, helping Klaviyo extend its best-in-class editing tools across platforms. How You Will Make a Difference: You will be a core member of the Editors team, working on impactful customer-facing features that will make our product the best in the industry. You will work on creating easy-to-use editors that are highly performant. You will work closely with Product, Design, and Data Science to provide the best experience for our customers. Who You Are: Experienced in full-stack development with strong hands-on skills in React, Redux, JavaScript, HTML, and CSS, along with familiarity with general web best practices. Has a track record of delivering and shipping work powered by or accelerated through AI. 3+ years of experience in a software engineering role Proficient in Python and Django (or similar backend technologies), and comfortable working across large codebases and multiple layers of the stack. Familiar with automated testing practices and frameworks, including end-to-end and integration tests (e.g., cypress, pytest). Experienced with RESTful and GraphQL APIs, and evolving APIs and data models to support product success. You take ownership of your work-from requirements and edge cases to implementation and testing-and are motivated by solving tough problems with others. Proven track record of leading complex, multi-quarter projects involving cross-team collaboration. You know when to reach for tools like queues, caches, CDNs, and web workers to solve performance and scaling challenges. Collaborative, communicative, and eager to learn and share knowledge. Technologies We Use (not exhaustive): React, TypeScript, Redux Python, Django MySQL, RabbitMQ, Redis, ProxySQL Amazon Web Services (EC2, RDS, Aurora, etc.), Terraform, and other DevOps tools Location: This is a hybrid role based in Boston, with 3 days in office and 2 days remote per week. We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025. Please see the independent bias audit report covering our use of Covey here Massachusetts Applicants: It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability. Our salary range reflects the cost of labor across various U.S. geographic markets. The range displayed below reflects the minimum and maximum target salaries for the position across all our US locations. The base salary offered for this position is determined by several factors, including the applicant's job-related skills, relevant experience, education or training, and work location. In addition to base salary, our total compensation package may include participation in the company's annual cash bonus plan, variable compensation (OTE) for sales and customer success roles, equity, sign-on payments, and a comprehensive range of health, welfare, and wellbeing benefits based on eligibility. Your recruiter can provide more details about the specific salary/OTE range for your preferred location during the hiring process. Base Pay Range For US Locations:$120,000-$180,000 USD Get to Know Klaviyo We're Klaviyo (pronounced clay-vee-oh). We empower creators to own their destiny by making first-party data accessible and actionable like never before. We see limitless potential for the technology we're developing to nurture personalized experiences in ecommerce and beyond. To reach our goals, we need our own crew of remarkable creators-ambitious and collaborative teammates who stay focused on our north star: delighting our customers. If you're ready to do the best work of your career, where you'll be welcomed as your whole self from day one and supported with generous benefits, we hope you'll join us. AI fluency at Klaviyo includes responsible use of AI (including privacy, security, bias awareness, and human-in-the-loop). We provide accommodations as needed. By participating in Klaviyo's interview process, you acknowledge that you have read, understood, and will adhere to our Guidelines for using AI in the Klaviyo interview Process. For more information about how we process your personal data, see our Job Applicant Privacy Notice. Klaviyo is committed to a policy of equal opportunity and non-discrimination. We do not discriminate on the basis of race, ethnicity, citizenship, national origin, color, religion or religious creed, age, sex (including pregnancy), gender identity, sexual orientation, physical or mental disability, veteran or active military status, marital status, criminal record, genetics, retaliation, sexual harassment or any other characteristic protected by applicable law. IMPORTANT NOTICE: Our company takes the security and privacy of job applicants very seriously. We will never ask for payment, bank details, or personal financial information as part of the application process. All our legitimate job postings can be found on our official career site. Please be cautious of job offers that come from non-company email addresses (@klaviyo.com), instant messaging platforms, or unsolicited calls. By clicking "Submit Application" you consent to Klaviyo processing your Personal Data in accordance with our Job Applicant Privacy Notice. If you do not wish for Klaviyo to process your Personal Data, please do not submit an application. You can find our Job Applicant Privacy Notice here and here (FR).

Job Description At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you're a close but not exact match with the description, we hope you'll still consider applying. Want to learn more about life at Klaviyo? Visit careers.klaviyo.com to see how we empower creators to own their own destiny. Klaviyo is growing fast and we have openings for all skill levels across all of our teams. Learn more about our engineering culture at ******************** We love tackling tough engineering problems and look for Engineers who specialize in certain areas but are passionate about building, owning & scaling features end to end from scratch and breaking through any obstacle or technical challenge in their way. We push each other to move out of our comfort zone, learn new technologies and work hard to ensure each day is better than the last. Klaviyo operates a real-time data platform coded in Python built for massive scale on Amazon Web Services (AWS). Engineers come to Klaviyo with experience in a variety of languages and from a number of disciplines. Team Overview: DevX is a hybrid product-platform team focused on empowering external developers and partners by supporting applications they build on top of Klaviyo's Public APIs and features. Examples of these areas of ownership include: our Application directory, which is used to promote and allow Klaviyo customers to discover applications that they can enable for their account the self-serve application process for a Partner to submit an Application and the ability for Klaviyo staff to review and approve an Application API Analytics is a system used by developers and partners to diagnose issues in their applications and understand their API usage. It is powered by a near real-time data pipeline that processes over 160,000 events per second. Autogenerated API docs, SDKs, CLIs & MCP servers Responsibilities: You will have an opportunity to make a major impact on the direction and priorities of the team. As an engineer on this team, you will work on Klaviyo's app marketplace, application publishing workflows, and the developer-facing tools and systems that support our app ecosystem. Additional responsibilities include providing quality PR reviews for our code-owned areas of the application, collaborating with product owners and providing technical expertise on upcoming Product Specifications, and participating in the definition of well-defined, estimated, and planned scopes of work. Required Skills: 3-5+ years of experience in a software engineering discipline Experience with full stack application development Experience working with both monolithic and microservices architectures Experience with CI/CD pipelines Experience debugging performance issues and improving application performance Team Tech Stack: Python Django REST Framework, Django, fast API React, React Query MySQL / postgre SQL DocumentDB Clickhouse JSON Forms Redis Memcached RabbitMQ / Celery / Apache Pulsar Preferred Skills: Experience working with Service Oriented Architecture (preferably in Python) Experience working with RESTful applications/APIs/gRPC We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025. Please see the independent bias audit report covering our use of Covey here Massachusetts Applicants: It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability. Our salary range reflects the cost of labor across various U.S. geographic markets. The range displayed below reflects the minimum and maximum target salaries for the position across all our US locations. The base salary offered for this position is determined by several factors, including the applicant's job-related skills, relevant experience, education or training, and work location. In addition to base salary, our total compensation package may include participation in the company's annual cash bonus plan, variable compensation (OTE) for sales and customer success roles, equity, sign-on payments, and a comprehensive range of health, welfare, and wellbeing benefits based on eligibility. Your recruiter can provide more details about the specific salary/OTE range for your preferred location during the hiring process. Base Pay Range For US Locations:$120,000-$180,000 USD Get to Know Klaviyo We're Klaviyo (pronounced clay-vee-oh). We empower creators to own their destiny by making first-party data accessible and actionable like never before. We see limitless potential for the technology we're developing to nurture personalized experiences in ecommerce and beyond. To reach our goals, we need our own crew of remarkable creators-ambitious and collaborative teammates who stay focused on our north star: delighting our customers. If you're ready to do the best work of your career, where you'll be welcomed as your whole self from day one and supported with generous benefits, we hope you'll join us. AI fluency at Klaviyo includes responsible use of AI (including privacy, security, bias awareness, and human-in-the-loop). We provide accommodations as needed. By participating in Klaviyo's interview process, you acknowledge that you have read, understood, and will adhere to our Guidelines for using AI in the Klaviyo interview Process. For more information about how we process your personal data, see our Job Applicant Privacy Notice. Klaviyo is committed to a policy of equal opportunity and non-discrimination. We do not discriminate on the basis of race, ethnicity, citizenship, national origin, color, religion or religious creed, age, sex (including pregnancy), gender identity, sexual orientation, physical or mental disability, veteran or active military status, marital status, criminal record, genetics, retaliation, sexual harassment or any other characteristic protected by applicable law. IMPORTANT NOTICE: Our company takes the security and privacy of job applicants very seriously. We will never ask for payment, bank details, or personal financial information as part of the application process. All our legitimate job postings can be found on our official career site. Please be cautious of job offers that come from non-company email addresses (@klaviyo.com), instant messaging platforms, or unsolicited calls. By clicking "Submit Application" you consent to Klaviyo processing your Personal Data in accordance with our Job Applicant Privacy Notice. If you do not wish for Klaviyo to process your Personal Data, please do not submit an application. You can find our Job Applicant Privacy Notice here and here (FR).

Job Description At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you're a close but not exact match with the description, we hope you'll still consider applying. Want to learn more about life at Klaviyo? Visit careers.klaviyo.com to see how we empower creators to own their own destiny. Why You Should Join the Editors Team: The Editors team is responsible for building common reusable components for the message editor. This team powers all the editors at Klaviyo. This team focuses on building intuitive and powerful interfaces to create highly customizable and dynamic content ranging from product feeds, real time event data, and more. This product area is core to Klaviyo's continued success. As a Software Engineer II on the team, you'll play a key role in designing and building scalable systems that power our editor experiences across all the editors. Partnering closely with product managers and technical product owners, you'll help define scope, translate ideas into practical implementations, and build intuitive editing tools that delight our users. This role leans frontend, with a strong focus on crafting thoughtful, reusable components and seamless user experiences using technologies like TypeScript, React, Python, and Django. There are ample opportunities for growth given the scope of this role and the team's central role in Klaviyo's product. Over the past year, our team has enhanced the editor interfaces with impactful features that our customers love-and they're eager to see that same power brought to other mobile experiences. Looking ahead, we'll be investing in new editor blocks, a personalization builder, in-canvas editing, and content generation powered by AI. You'll contribute directly to these efforts, helping Klaviyo extend its best-in-class editing tools across platforms. How You Will Make a Difference: You will be a core member of the Editors team, working on impactful customer-facing features that will make our product the best in the industry. You will work on creating easy-to-use editors that are highly performant. You will work closely with Product, Design, and Data Science to provide the best experience for our customers. Who You Are: Experienced in full-stack development with strong hands-on skills in React, Redux, JavaScript, HTML, and CSS, along with familiarity with general web best practices. Has a track record of delivering and shipping work powered by or accelerated through AI. 3+ years of experience in a software engineering role Proficient in Python and Django (or similar backend technologies), and comfortable working across large codebases and multiple layers of the stack. Familiar with automated testing practices and frameworks, including end-to-end and integration tests (e.g., cypress, pytest). Experienced with RESTful and GraphQL APIs, and evolving APIs and data models to support product success. You take ownership of your work-from requirements and edge cases to implementation and testing-and are motivated by solving tough problems with others. Proven track record of leading complex, multi-quarter projects involving cross-team collaboration. You know when to reach for tools like queues, caches, CDNs, and web workers to solve performance and scaling challenges. Collaborative, communicative, and eager to learn and share knowledge. Technologies We Use (not exhaustive): React, TypeScript, Redux Python, Django MySQL, RabbitMQ, Redis, ProxySQL Amazon Web Services (EC2, RDS, Aurora, etc.), Terraform, and other DevOps tools Location: This is a hybrid role based in Boston, with 3 days in office and 2 days remote per week. We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025. Please see the independent bias audit report covering our use of Covey here Massachusetts Applicants: It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability. Our salary range reflects the cost of labor across various U.S. geographic markets. The range displayed below reflects the minimum and maximum target salaries for the position across all our US locations. The base salary offered for this position is determined by several factors, including the applicant's job-related skills, relevant experience, education or training, and work location. In addition to base salary, our total compensation package may include participation in the company's annual cash bonus plan, variable compensation (OTE) for sales and customer success roles, equity, sign-on payments, and a comprehensive range of health, welfare, and wellbeing benefits based on eligibility. Your recruiter can provide more details about the specific salary/OTE range for your preferred location during the hiring process. Base Pay Range For US Locations:$120,000-$180,000 USD Get to Know Klaviyo We're Klaviyo (pronounced clay-vee-oh). We empower creators to own their destiny by making first-party data accessible and actionable like never before. We see limitless potential for the technology we're developing to nurture personalized experiences in ecommerce and beyond. To reach our goals, we need our own crew of remarkable creators-ambitious and collaborative teammates who stay focused on our north star: delighting our customers. If you're ready to do the best work of your career, where you'll be welcomed as your whole self from day one and supported with generous benefits, we hope you'll join us. AI fluency at Klaviyo includes responsible use of AI (including privacy, security, bias awareness, and human-in-the-loop). We provide accommodations as needed. By participating in Klaviyo's interview process, you acknowledge that you have read, understood, and will adhere to our Guidelines for using AI in the Klaviyo interview Process. For more information about how we process your personal data, see our Job Applicant Privacy Notice. Klaviyo is committed to a policy of equal opportunity and non-discrimination. We do not discriminate on the basis of race, ethnicity, citizenship, national origin, color, religion or religious creed, age, sex (including pregnancy), gender identity, sexual orientation, physical or mental disability, veteran or active military status, marital status, criminal record, genetics, retaliation, sexual harassment or any other characteristic protected by applicable law. IMPORTANT NOTICE: Our company takes the security and privacy of job applicants very seriously. We will never ask for payment, bank details, or personal financial information as part of the application process. All our legitimate job postings can be found on our official career site. Please be cautious of job offers that come from non-company email addresses (@klaviyo.com), instant messaging platforms, or unsolicited calls. By clicking "Submit Application" you consent to Klaviyo processing your Personal Data in accordance with our Job Applicant Privacy Notice. If you do not wish for Klaviyo to process your Personal Data, please do not submit an application. You can find our Job Applicant Privacy Notice here and here (FR).

At Klaviyo, we believe the future of software lies not in productivity tools for human users but in systems that do the hard work for them. We've built the infrastructure and applications that power the interface between businesses and consumers - supporting over 167,000 customers, billions of consumer profiles, and hundreds of billions of customer interactions. Now, we're building the next generation of AI agents that can automatically create, execute, and optimize marketing and customer experience strategies for any business. As a Senior Software Engineer at Klaviyo on the Marketing Agent team, you'll play a key role in designing and building the system that autonomously creates and executes high impact marketing strategies on behalf of our customers. Partnering closely with product managers and technical product owners, you'll help define scope, translate ideas into practical implementations, and build intuitive tools that delight our customers. This role is primarily backend, with a strong focus on crafting robust and maintainable AI powered systems that deliver high quality strategies and marketing content that's ready to use to our customers. There are ample opportunities for growth given the scope of this role and the team's central role in Klaviyo's product. How you'll make a difference: * You will dramatically increase ROI for Klaviyo customers by automating most of the marketing process for them. * You will lead and design the next generation of agentic systems at Klaviyo, pushing the frontier of AI capabilities. * You will collaborate with AI Engineers and AI Infra Engineers to ensure our system consistently produces high quality outputs at low latency. * You will leverage your experience to mentor and level up junior team members on engineering best practices and patterns. * You will transform workflows by putting AI at the center, building smarter systems and ways of working from the ground up. Who you are: * A proven track record of building high-quality products and systems, with pride in writing clean, high-quality code. * 7+ years of experience in a software engineering role. * Experience leading projects and being accountable for their outcomes. * Experience mentoring team members or driving initiatives that help the team learn new skills. * Experience conducting code reviews and running a robust testing cycle. * Experience working in agile, fast-paced environments. * Proficient in Python and modern web stack components such as FastAPI, Django, MySQL, Postgres. * Experience working in cloud environments (AWS preferred). * You've already experimented with AI in work or personal projects, and you're excited to dive in and learn fast. You're hungry to responsibly explore new AI tools and workflows, finding ways to make your work smarter and more efficient. Nice to have: * Prior work experience with AI tools such as Arize, Langgraph, Langchain * Prior work experience building with LLMs such as GPT, Gemini, Claude We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025. Please see the independent bias audit report covering our use of Covey here

About the Role Our team is looking for a Senior Full Stack Engineer to lead key initiatives that will enhance our product offerings and support our company's growth. In this role, you'll play a crucial part in shaping outcomes by developing innovative end-to-end solutions using both front-end and back-end technologies. You'll optimize existing products and create new solutions that redefine what's possible for our customers. As a Senior Engineer, you'll tackle complex challenges, develop multiple solutions, and evaluate business and technical trade-offs to determine the best path forward. You'll also act as a leader and mentor, and drive key technology decisions. Additionally, you'll be responsible for deploying well-designed, thoroughly tested solutions that ensure reliability and performance. The New Products team drives Klaviyo's most ambitious innovations-creating and scaling the company's boldest new bets. As a nimble group with a flat structure and fast-moving culture, we prioritize simplicity, speed, and impact. Every team member is expected to take radical ownership-rolling up their sleeves, collaborating across disciplines, and pushing beyond traditional role boundaries to make things happen. Success in this role means delivering exceptional work that sets the standard for velocity and results company-wide, while helping shape Klaviyo's future through experimentation, creativity, and executional excellence. What We're Looking For A proven track record of building high-quality products and systems, with pride in writing clean, high-quality code. 7+ years of experience in a software engineering role. Strong experience developing end-to-end software solutions or extensive experience with both front-end and back-end technologies. Experience leading projects and being accountable for their outcomes. Experience mentoring team members or driving initiatives that help the team learn new skills. Experience conducting code reviews and running a robust testing cycle. Experience working in agile, fast-paced environments. You've already experimented with AI in work or personal projects, and you're excited to dive in and learn fast. You're hungry to responsibly explore new AI tools and workflows, finding ways to make your work smarter and more efficient. Transform workflows by putting AI at the center, building smarter systems and ways of working from the ground up. Nice to Have Skills with Python and related technologies Skills with React and related technologies Experience developing digital marketing or customer data software solutions. Experience with machine learning. Experience building cloud-native solutions, ideally with AWS. We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025. Please see the independent bias audit report covering our use of Covey here

At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you're a close but not exact match with the description, we hope you'll still consider applying. Want to learn more about life at Klaviyo? Visit careers.klaviyo.com to see how we empower creators to own their own destiny. Klaviyo is seeking a Web Growth Manager to evolve our global web experience with a sharp focus on growth, funnel optimization, and AI-powered personalization. This role will execute strategies that drive top-of-funnel acquisition, optimize visitor-to-lead conversion, and build personalized, scalable digital experiences. You'll partner cross-functionally with Marketing, Engineering, UX, and other stakeholders to build innovative, data-driven web journeys that directly impact pipeline and revenue growth. This is a unique opportunity to sit at the intersection of AI innovation, growth strategy, and digital experience design-helping Klaviyo scale its digital presence while delivering world-class journeys for our diverse B2B customer segments. How You Will Make a Difference: Own and accelerate product-led conversion & personalized experiences across klaviyo.com - designing experiences that let visitors try, learn, and convert directly through interactive free tools, demos and guided product exploration. Build, test, and optimize free tools and self-serve demo experiences (using platforms like Navattic) to showcase product value early in the buyer journey. Prioritize and deliver initiatives that strengthen the bridge between website engagement, interactive free tools, and product activation, including optimizing the back end CMS capabilities to support front end build. Lead discovery efforts grounded in user behavior, funnel data, and competitive benchmarks to identify opportunities for innovation in the self-serve & growth experience. Partner with Product Marketing, Demand Gen, and Growth Engineering to ensure PLG & personalized experiences drive qualified, high-intent leads into the sales and onboarding funnel. Support a 6-12 month roadmap for product-led web experiences and personalization - aligning with Klaviyo's growth and self-serve acquisition strategy. Collaborate with Design and UX to maintain seamless, high-performing experiences that communicate product value intuitively and beautifully. Who You Are: 8+ years of product management experience, including 4+ years in growth or web product. Proven success driving measurable top-of-funnel growth & conversion optimization for B2B SaaS companies via personalization & experimentation. Hands-on experience implementing AI-powered features in digital products. Strong background in web analytics, experimentation, and funnel analysis. Proficiency with analytics tools (Google Analytics, Tableau), A/B testing platforms, Product demo platforms, and CMS. Understanding of SEO, marketing automation, and lead management platforms. Ability to define product roadmaps, write detailed requirements, and deliver with agile teams. Strong analytical mindset, experience in growth hacking via experimentation and PLG. Excellent communication skills, ability to influence both technical and executive stakeholders. Experience scaling global websites across multiple languages and markets Knowledge of B2B SaaS product growth models We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025. Please see the independent bias audit report covering our use of Covey here Massachusetts Applicants: It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability. Our salary range reflects the cost of labor across various U.S. geographic markets. The range displayed below reflects the minimum and maximum target salaries for the position across all our US locations. The base salary offered for this position is determined by several factors, including the applicant's job-related skills, relevant experience, education or training, and work location. In addition to base salary, our total compensation package may include participation in the company's annual cash bonus plan, variable compensation (OTE) for sales and customer success roles, equity, sign-on payments, and a comprehensive range of health, welfare, and wellbeing benefits based on eligibility. Your recruiter can provide more details about the specific salary/OTE range for your preferred location during the hiring process. Base Pay Range For US Locations:$148,000-$222,000 USD Get to Know Klaviyo We're Klaviyo (pronounced clay-vee-oh). We empower creators to own their destiny by making first-party data accessible and actionable like never before. We see limitless potential for the technology we're developing to nurture personalized experiences in ecommerce and beyond. To reach our goals, we need our own crew of remarkable creators-ambitious and collaborative teammates who stay focused on our north star: delighting our customers. If you're ready to do the best work of your career, where you'll be welcomed as your whole self from day one and supported with generous benefits, we hope you'll join us. AI fluency at Klaviyo includes responsible use of AI (including privacy, security, bias awareness, and human-in-the-loop). We provide accommodations as needed. By participating in Klaviyo's interview process, you acknowledge that you have read, understood, and will adhere to our Guidelines for using AI in the Klaviyo interview Process. For more information about how we process your personal data, see our Job Applicant Privacy Notice. Klaviyo is committed to a policy of equal opportunity and non-discrimination. We do not discriminate on the basis of race, ethnicity, citizenship, national origin, color, religion or religious creed, age, sex (including pregnancy), gender identity, sexual orientation, physical or mental disability, veteran or active military status, marital status, criminal record, genetics, retaliation, sexual harassment or any other characteristic protected by applicable law. IMPORTANT NOTICE: Our company takes the security and privacy of job applicants very seriously. We will never ask for payment, bank details, or personal financial information as part of the application process. All our legitimate job postings can be found on our official career site. Please be cautious of job offers that come from non-company email addresses (@klaviyo.com), instant messaging platforms, or unsolicited calls. By clicking "Submit Application" you consent to Klaviyo processing your Personal Data in accordance with our Job Applicant Privacy Notice. If you do not wish for Klaviyo to process your Personal Data, please do not submit an application. You can find our Job Applicant Privacy Notice here and here (FR).

Job Description At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you're a close but not exact match with the description, we hope you'll still consider applying. Want to learn more about life at Klaviyo? Visit careers.klaviyo.com to see how we empower creators to own their own destiny. Klaviyo is seeking a Web Growth Manager to evolve our global web experience with a sharp focus on growth, funnel optimization, and AI-powered personalization. This role will execute strategies that drive top-of-funnel acquisition, optimize visitor-to-lead conversion, and build personalized, scalable digital experiences. You'll partner cross-functionally with Marketing, Engineering, UX, and other stakeholders to build innovative, data-driven web journeys that directly impact pipeline and revenue growth. This is a unique opportunity to sit at the intersection of AI innovation, growth strategy, and digital experience design-helping Klaviyo scale its digital presence while delivering world-class journeys for our diverse B2B customer segments. How You Will Make a Difference: Own and accelerate product-led conversion & personalized experiences across klaviyo.com - designing experiences that let visitors try, learn, and convert directly through interactive free tools, demos and guided product exploration. Build, test, and optimize free tools and self-serve demo experiences (using platforms like Navattic) to showcase product value early in the buyer journey. Prioritize and deliver initiatives that strengthen the bridge between website engagement, interactive free tools, and product activation, including optimizing the back end CMS capabilities to support front end build. Lead discovery efforts grounded in user behavior, funnel data, and competitive benchmarks to identify opportunities for innovation in the self-serve & growth experience. Partner with Product Marketing, Demand Gen, and Growth Engineering to ensure PLG & personalized experiences drive qualified, high-intent leads into the sales and onboarding funnel. Support a 6-12 month roadmap for product-led web experiences and personalization - aligning with Klaviyo's growth and self-serve acquisition strategy. Collaborate with Design and UX to maintain seamless, high-performing experiences that communicate product value intuitively and beautifully. Who You Are: 8+ years of product management experience, including 4+ years in growth or web product. Proven success driving measurable top-of-funnel growth & conversion optimization for B2B SaaS companies via personalization & experimentation. Hands-on experience implementing AI-powered features in digital products. Strong background in web analytics, experimentation, and funnel analysis. Proficiency with analytics tools (Google Analytics, Tableau), A/B testing platforms, Product demo platforms, and CMS. Understanding of SEO, marketing automation, and lead management platforms. Ability to define product roadmaps, write detailed requirements, and deliver with agile teams. Strong analytical mindset, experience in growth hacking via experimentation and PLG. Excellent communication skills, ability to influence both technical and executive stakeholders. Experience scaling global websites across multiple languages and markets Knowledge of B2B SaaS product growth models We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025. Please see the independent bias audit report covering our use of Covey here Massachusetts Applicants: It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability. Our salary range reflects the cost of labor across various U.S. geographic markets. The range displayed below reflects the minimum and maximum target salaries for the position across all our US locations. The base salary offered for this position is determined by several factors, including the applicant's job-related skills, relevant experience, education or training, and work location. In addition to base salary, our total compensation package may include participation in the company's annual cash bonus plan, variable compensation (OTE) for sales and customer success roles, equity, sign-on payments, and a comprehensive range of health, welfare, and wellbeing benefits based on eligibility. Your recruiter can provide more details about the specific salary/OTE range for your preferred location during the hiring process. Base Pay Range For US Locations:$148,000-$222,000 USD Get to Know Klaviyo We're Klaviyo (pronounced clay-vee-oh). We empower creators to own their destiny by making first-party data accessible and actionable like never before. We see limitless potential for the technology we're developing to nurture personalized experiences in ecommerce and beyond. To reach our goals, we need our own crew of remarkable creators-ambitious and collaborative teammates who stay focused on our north star: delighting our customers. If you're ready to do the best work of your career, where you'll be welcomed as your whole self from day one and supported with generous benefits, we hope you'll join us. AI fluency at Klaviyo includes responsible use of AI (including privacy, security, bias awareness, and human-in-the-loop). We provide accommodations as needed. By participating in Klaviyo's interview process, you acknowledge that you have read, understood, and will adhere to our Guidelines for using AI in the Klaviyo interview Process. For more information about how we process your personal data, see our Job Applicant Privacy Notice. Klaviyo is committed to a policy of equal opportunity and non-discrimination. We do not discriminate on the basis of race, ethnicity, citizenship, national origin, color, religion or religious creed, age, sex (including pregnancy), gender identity, sexual orientation, physical or mental disability, veteran or active military status, marital status, criminal record, genetics, retaliation, sexual harassment or any other characteristic protected by applicable law. IMPORTANT NOTICE: Our company takes the security and privacy of job applicants very seriously. We will never ask for payment, bank details, or personal financial information as part of the application process. All our legitimate job postings can be found on our official career site. Please be cautious of job offers that come from non-company email addresses (@klaviyo.com), instant messaging platforms, or unsolicited calls. By clicking "Submit Application" you consent to Klaviyo processing your Personal Data in accordance with our Job Applicant Privacy Notice. If you do not wish for Klaviyo to process your Personal Data, please do not submit an application. You can find our Job Applicant Privacy Notice here and here (FR).

As the Software Engineer, Product Recommendations at Klaviyo, you'll help build the machine learning-powered systems that decide which products to show to whom and when across our platform. You'll work on large-scale backend and data systems that turn billions of behavioral events into real-time, personalized product recommendations that drive revenue for merchants of all sizes. You'll join the Product Recommendation team, partnering closely with Machine Learning Engineers, AI Engineers, other engineers, Product Managers and Designers to design, build, and operate services and data pipelines that power our recommendation features end to end-from data ingestion and feature generation to ranking models and APIs exposed in product. This is a hands-on backend role with a strong focus on building scalable systems and data processing frameworks, with prior ML system experience as a plus (not a hard requirement). How you'll make a difference Design, build, and operate backend services that power product recommendations across Klaviyo experiences (email, SMS, KAgent, onsite, etc.), with a focus on reliability, performance, and clear APIs. Build and maintain large-scale data processing pipelines (e.g., using Apache Spark or similar frameworks) that transform raw events and catalog data into high-quality features and inputs for recommendation models. Collaborate with ML engineers to productionize recommendation models-defining interfaces, feature contracts, and deployment patterns for batch and/or real-time inference. Build ML/AI systems such as vector search that power recommendation, semantic search, and agentic use cases. Implement and evolve data and service observability (metrics, logging, tracing, dashboards) to ensure recommendations are correct, fast, and available when customers need them. Contribute to and improve shared data frameworks, libraries, and patterns that make it easier to build new recommendation use cases and iterate quickly. Work with product managers to break down complex recommendation initiatives into clear milestones, helping balance experimentation speed with reliability and technical soundness. Partner on data-driven decision making and A/B testing-ensuring recommendation systems are instrumented with the right metrics, and helping interpret results to guide future iterations. Participate in on-call and incident response for the systems you own, driving follow-ups that improve the resilience and operability of our recommendation stack. Transform workflows by putting AI at the center, building smarter systems and ways of working from the ground up-for example, using AI to accelerate development, automate tests, or better monitor and debug recommendation behavior. Share knowledge and mentor other engineers on working with large-scale data frameworks, distributed systems, and best practices for integrating ML into production systems. Who you are 3+ years of software engineering experience, including building and operating backend services in production. Strong focus on backend and distributed systems at scale; you've worked on high-throughput or highly available services and care about latency, reliability, and operability. Proficient in Python, and comfortable working in at least one modern language used for backend/data work (e.g., Java or Scala). Proficient with big data frameworks such as Apache Spark (or similar technologies like Flink, Beam, etc.) for building batch or streaming pipelines. Comfortable with cloud-native architectures (AWS preferred) and container orchestration (e.g., Kubernetes); able to work with infrastructure and CI/CD pipelines as part of your day-to-day development. Comfortable with data-driven decision making and A/B testing-you understand how to instrument experiments, read results, and fold learnings back into the system. Comfortable designing and querying data models in relational or analytical datastores (e.g., Postgres, MySQL, data warehouses). Familiarity with modern DevOps practices (CI/CD, monitoring, alerting) and how they apply to large-scale data and recommendation systems. Proven track record of owning projects end-to-end-from design and implementation through rollout, monitoring, and iteration-ideally across multiple components or services. Excellent collaborator and communicator: you can explain tradeoffs to technical and non-technical partners and work effectively with ML Engineers, Software Engineers, PMs, and other teams. You've already experimented with AI in work or personal projects, and you're excited to dive in and learn fast. You're hungry to responsibly explore new AI tools and workflows, finding ways to make your work smarter and more efficient. Nice to haves Previous experience working on product recommendation systems or adjacent ML-powered features (ranking, personalization, search, or similar). Experience in AI/ML systems and products, such as integrating models into production systems or building features powered by ML. Experience training machine learning models (e.g., for ranking, prediction, or personalization), even if you don't consider yourself a full-time ML engineer. Experience with ML and distributed compute frameworks such as Ray or similar tools. Experience partnering with data science or ML teams to productionize models (feature stores, offline/online parity, model deployment and monitoring). Experience with additional data technologies (e.g., Kafka, Kinesis, Redis, feature stores, or vector databases). Background in e-commerce, marketing tech, or consumer personalization products

Why You Should Join the Editors Team: The Editors team is responsible for building common reusable components for the message editor. This team powers all the editors at Klaviyo. This team focuses on building intuitive and powerful interfaces to create highly customizable and dynamic content ranging from product feeds, real time event data, and more. This product area is core to Klaviyo's continued success. As a Software Engineer II on the team, you'll play a key role in designing and building scalable systems that power our editor experiences across all the editors. Partnering closely with product managers and technical product owners, you'll help define scope, translate ideas into practical implementations, and build intuitive editing tools that delight our users. This role leans frontend, with a strong focus on crafting thoughtful, reusable components and seamless user experiences using technologies like TypeScript, React, Python, and Django. There are ample opportunities for growth given the scope of this role and the team's central role in Klaviyo's product. Over the past year, our team has enhanced the editor interfaces with impactful features that our customers love-and they're eager to see that same power brought to other mobile experiences. Looking ahead, we'll be investing in new editor blocks, a personalization builder, in-canvas editing, and content generation powered by AI. You'll contribute directly to these efforts, helping Klaviyo extend its best-in-class editing tools across platforms. How You Will Make a Difference: * You will be a core member of the Editors team, working on impactful customer-facing features that will make our product the best in the industry. * You will work on creating easy-to-use editors that are highly performant. * You will work closely with Product, Design, and Data Science to provide the best experience for our customers. Who You Are: * Experienced in full-stack development with strong hands-on skills in React, Redux, JavaScript, HTML, and CSS, along with familiarity with general web best practices. * Has a track record of delivering and shipping work powered by or accelerated through AI. * 3+ years of experience in a software engineering role * Proficient in Python and Django (or similar backend technologies), and comfortable working across large codebases and multiple layers of the stack. * Familiar with automated testing practices and frameworks, including end-to-end and integration tests (e.g., cypress, pytest). * Experienced with RESTful and GraphQL APIs, and evolving APIs and data models to support product success. * You take ownership of your work-from requirements and edge cases to implementation and testing-and are motivated by solving tough problems with others. * Proven track record of leading complex, multi-quarter projects involving cross-team collaboration. * You know when to reach for tools like queues, caches, CDNs, and web workers to solve performance and scaling challenges. * Collaborative, communicative, and eager to learn and share knowledge. Technologies We Use (not exhaustive): * React, TypeScript, Redux * Python, Django * MySQL, RabbitMQ, Redis, ProxySQL * Amazon Web Services (EC2, RDS, Aurora, etc.), Terraform, and other DevOps tools Location: This is a hybrid role based in Boston, with 3 days in office and 2 days remote per week. We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025. Please see the independent bias audit report covering our use of Covey here