Greenhouse · Posted 22 Sept 2026

full-time

Software Engineer II, Test Frameworks & Tooling

Klaviyo · Boston, MA

Klaviyo is a company in the marketing automation space that provides tools for e‑commerce businesses to manage email and SMS campaigns. The Software Engineer II, Test Frameworks & Tooling internship focuses on building and maintaining the infrastructure that supports reliable software releases. Day‑to‑day work includes owning and enhancing integration and end‑to‑end testing frameworks across backend and frontend stacks, improving how tests run in the CI/CD pipeline, defining repository standards for unit tests and code quality, and developing scalable tools for data mocking, service isolation, and test coverage. The role also involves exploring AI‑powered techniques for regression detection, flaky test analysis, and intelligent test generation, as well as collaborating with feature teams to troubleshoot unstable tests and monitor the health of test suites and pipelines. Candidates should have strong analytical problem‑solving skills, at least two years of software engineering experience writing clean, maintainable code, and a track record of debugging complex issues and driving systemic improvements.

test framework engineeringci/cd integrationautomated testinge2e testingai-driven qualitysoftware engineer iitest toolingrepository standardsflaky test analysis

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 klaviyo.com/careers to see how we empower creators to own their own destiny. Why You Should Join the Test Frameworks and Tooling Team Engineering confidence is our primary product. We are not testers, but rather infrastructure engineers building the sophisticated automation and CI/CD frameworks that make deploying to production a non-event. Our mission is to architect the systems, repository standards, and automated guardrails that empower every engineer in the company to ship at terminal velocity with total confidence. By building the foundational tools that guarantee production readiness, you will play a direct role in driving Sev-1 incidents toward zero and ensuring that our organization can move fast without the fear of breaking things. What You'll Achieve: Key Responsibilities As a core member of the team, you will own the execution of critical projects and contribute to the evolution of our testing ecosystem: Own and Enhance Frameworks: Take ownership of our integration and E2E testing frameworks across both backend and frontend stacks. You will ensure they are fast, reliable, and easy for other teams to adopt. CI/CD Integration: Contribute to how we execute tests within our CI system. You will focus on optimizing feedback loops so engineers know exactly where they stand in minutes. Establish Standards: Help define and implement general rules for our repositories, ensuring consistency in how unit tests are written and how code quality is measured. Scalable Feature & Coverage Contribution: Actively develop new tools that simplify complex testing scenarios while identifying and backfilling critical testing gaps at scale. You will build systems for data mocking and service isolation that ensure high-fidelity coverage across our most complex application flows. AI-Driven Quality Innovation: Help lead the charge in leveraging AI to accelerate our testing lifecycle. You will explore and implement AI-powered tools for automated regression detection, flaky test analysis, and intelligent test generation to decrease time-to-completion for features. Collaborative Problem Solving: Partner with feature teams to troubleshoot flaky tests and identify gaps in our current coverage, making proactive suggestions to improve our overall safety net. Operational Excellence: Monitor the health of our test suites and CI pipelines, taking pride in maintaining a stable and performant environment for the entire engineering organization. What Makes This Role Exciting Direct Impact on Stability: Your work is the primary line of defense against Sev 1 incidents. When the platform stays up and customers stay happy, it is because of the systems you help maintain. Full-Stack Visibility: Because you own the E2E suite, you will gain a deep understanding of how our entire ecosystem fits together, from frontend UI components to complex backend microservices. Autonomy and Growth: While we provide the vision, you provide the execution. You will have the space to own your work end-to-end, propose technical improvements, and see your suggestions implemented company-wide. High-Leverage Work: You are not just building one feature for one customer. You are building the tools that hundreds of your fellow engineers use every single day to do their jobs better. Who You Are: Analytical Problem Solver: You have 2+ years of software engineering experience with a focus on writing clean, maintainable code. You excel at debugging complex issues and performing root-cause analysis, using those learnings to implement systemic improvements that prevent future regressions. Quality Advocate: You find satisfaction in a well-organized test suite. You understand that testing is a fundamental part of the development lifecycle, not an afterthought. Technical Generalist: You are comfortable working across the stack. Whether it is debugging a React component in an E2E test or optimizing a Python integration test, you are ready to dive in. AI-Forward Thinker: You are excited about the intersection of AI and Software Quality. You are eager to help us leverage AI to automate test generation, identify flaky patterns, and accelerate the overall development lifecycle. Ownership Mindset: You do not just wait for tickets. You look for ways to make things better. You take pride in owning a project from the initial PR to its successful deployment and monitoring. CI/CD Familiarity: You have experience with, or a strong desire to learn, CI/CD tools and understand how automated testing fits into a modern deployment pipeline. Technologies w

Role	Software Engineer II, Test Frameworks & Tooling
Company	Klaviyo
Location	Boston, MA
Compensation	Not disclosed
Posted	2026-09-25
Deadline	Rolling

Typical process for this type of role

A general guide — the exact steps for this specific listing may vary; check the original posting for details.

1ApplicationSubmit your resume through the apply link.
2ScreeningRecruiter reviews your background against the role.
3AssessmentA technical test, assignment, or coding round, depending on the role.
4Interview(s)One or more rounds with the hiring team.
5OfferOffer letter with compensation and start date.

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About Klaviyo

Klaviyo, Inc. is an AI-first B2C CRM platform founded in 2012 and headquartered in Boston. The company provides a unified solution that integrates marketing automation, customer service, analytics, and a data platform to help businesses manage customer relationships. By centralizing behavioral, transactional, and engagement data, Klaviyo enables brands to deliver personalized, omnichannel campaigns across email, SMS, WhatsApp, and mobile push notifications. The platform utilizes AI agents to automate marketing tasks, resolve customer service inquiries, and optimize campaign performance. Klaviyo currently serves over 205,000 brands across more than 100 countries, processing billions of events and managing billions of customer profiles daily to support business growth.

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