Software Engineer I, Build Review & Test

About Handshake

In 2025, we started Handshake AI and built the fastest-growing AI data business in history. We work directly with frontier AI lab researchers to create evaluations, publish benchmarks, and push the boundary of data. We’ve grown from $0 to ~$1B run rate and pay ~$60M to over 30K individuals every month.

About Handshake AI

Human data is the core infrastructure to AI advancement. Frontier AI labs currently improve model capabilities with various data-intensive post-training techniques. We believe that data spend for AI training will increase by 3-5x in the next few years and continue for much longer as models take on new domains. Handshake AI supports all of the frontier AI labs, working on their most complex data at the largest scale.

The Role

We’re looking for a Software Engineer to make development at Handshake faster, more reliable, and easier to understand.

Coding agents are a core part of how our engineers work. Both need reliable tools, useful instructions, and clear feedback to produce code we can trust. You’ll build and improve tools that run builds and tests, review changes, and explain failures. Your work will help engineers and agents spend less time waiting or debugging and more time building.

You’ll care as much about how a tool feels to use as whether it works. Is it fast? Are the next steps clear? Does an error message help someone solve the problem? You’ll use developer surveys, conversations with engineers, and system data to guide improvements.

You don’t need a background in developer tools or AI. We’re looking for strong coding skills, curiosity, and a desire to make complex systems easier to use.

What You’ll Do

• Build and maintain tools for builds, tests, code review, and merging changes. Make them useful for both engineers and coding agents.
• Find and fix slow builds, unreliable tests, and confusing errors. Address the cause rather than asking users to work around the problem.
• Make tests faster and more reliable. Split work across machines, reuse previous results when safe, and keep tests from interfering with one another.
• Make failures easier to understand. Help users see what went wrong and what they can do next.
• Improve the tools, instructions, and environments that coding agents use to write, test, and debug code.
• Help build automated code reviews and checks. Reduce repetitive work while keeping clear standards for quality and safety.
• Use developer surveys and direct feedback to find problems worth solving. Work with teammates to release improvements safely, then check whether they made a difference.
• Share what you learn through documentation, code reviews, and working sessions with other engineers.

You Have

• About 3–5 years of professional software engineering experience, or comparable hands-on experience.
• Strong JavaScript or TypeScript skills and experience in the JavaScript ecosystem. Your background may be server-side, such as Node.js or Bun, or browser-based.
• Hands-on experience with JavaScript unit testing and end to end tests with tools like Jest, Vitest and Playwright.
• Experience shipping and maintaining production software, including writing automated tests.
• A careful approach to debugging. You test your assumptions and follow the evidence to find the cause.
• Curiosity about unfamiliar code and the patience to learn how a system works.
• A high bar for user experience. You notice small frustrations, listen to users, and care about the details that make tools easy to use.
• The ability to finish clearly defined projects on your own. You also know when to ask for help or work through a problem with a teammate.
• Clear communication and a willingness to give feedback, learn from others, and share what you know.

Extra Credit

You don’t need to know every tool we use. Any of the following would be helpful:

• Work on build systems or continuous integration (CI), using tools such as Buildkite, GitHub Actions, Docker, or Kubernetes.
• Experience building or extending test frameworks and shared libraries that make authoring tests more efficient and reliable.
• Experience making tests faster or fixing tests that fail without a code change.
• Hands-on use of coding agents, including giving them useful instructions and checking their results.
• Work on automated code review or testing, with or without AI.
• Experience making software builds and releases reliable and secure.
• Use of logs, metrics, or traces to investigate problems.

Perks

The below benefits are for full-time US employees.

🎯 Ownership: Equity in a fast-growing company

💰 Financial Wellness: 401(k) match, competitive compensation, financial coaching

🍼 Family Support: Paid parental leave, fertility benefits, parental coaching

💝 Wellbeing: Medical, dental, and vision, mental health support, $500 wellness stipend

📚 Growth: $2,000 learning stipend, ongoing development

💻 Remote & Office: Internet, commuting, and free lunch/gym in our SF office

🏝 Time Off: Flexible PTO, 15 holidays + 2 flex days

🤝 Connection: Team outings & referral bonuses

Explore our mission, values, and comprehensive US benefits at joinhandshake.com/careers.