New Products Principal Engineer

Why Mozilla?

Mozilla Corporation is the non-profit-backed technology company that has shaped the internet for the better over the last 25 years. We make pioneering brands like Firefox, the privacy-minded web browser. Now, with more than 225 million people around the world using our products each month, we’re shaping the next 25 years of technology and helping to reclaim an internet built for people, not companies. Our work focuses on diverse areas including AI, social media, security and more. And we’re doing this while never losing our focus on our core mission – to make the internet better for people.

The Mozilla Corporation is wholly owned by the non-profit 501(c) Mozilla Foundation. This means we aren’t beholden to any shareholders — only to our mission. Along with thousands of volunteer contributors and collaborators all over the world, Mozillians design, build and distribute open-source software that enables people to enjoy the internet on their terms.

The New Products team at Mozilla is building a browser-automation stack for AI agents. Our mission is to make it effortless for developers to integrate fast, reliable web interactions into their agentic applications.

We are seeking a founding Principal Software Engineer who will set the technical vision, architect the platform, and spend the majority of their time writing production code alongside the team. You will guide a small, fast-moving group of engineers, and personally deliver the core libraries, services, and tooling that empower the next generation of intelligent web automation. If you thrive on rolling up your sleeves, love shipping code that developers adore, and enjoy shaping green-field products from the ground up, we’d love to meet you.

• Technical Strategy & Architecture: Define and communicate the long-term technical roadmap for our browser-automation stack, balancing rapid iteration with long-term maintainability and scalability.
• Hands-On Development: Write elegant, high-performance code daily in languages such as Go, Ruby on Rails, and TypeScript. Rapidly prototype, benchmark, and ship features to production.
• System Design & Infrastructure: Design distributed, fault-tolerant services and developer-facing SDKs/APIs. Own cloud infrastructure, CI/CD pipelines, security, and observability.
• Team Leadership & Mentorship: Grow, mentor, and inspire a world-class engineering team. Conduct thoughtful code reviews, establish the engineering culture, and foster a team of technical excellence and psychological safety.
• Collaboration & Product Direction: Work closely with product, design, and developer-relations to ensure technical choices align with developer needs and business goals. Turn community feedback into concrete improvements.
• Stakeholder Communication: Translate complex technical trade-offs into clear language for executives, partners, and cross-functional teams. Provide regular updates on progress, risks, and mitigation strategies.

• 10+ years of software engineering experience building high-performance developer tools, SDKs, or distributed systems, with at least 3 years leading technical teams or large projects.
• Expert-level proficiency in at least two of: Go, Ruby (Rails), Python or TypeScript/JavaScript..
• Proven track record architecting and shipping complex, high-throughput systems in production environments (cloud, edge, or hybrid).
• Deep understanding of browser internals, automation frameworks (e.g., Playwright, Puppeteer, Selenium), and secure web interaction paradigms.
• Hands-on experience and opinions about modern AI/ML workflows or agent frameworks such as LangChain, LlamaIndex, or custom in-house systems.
• Strong focus on code quality, testability, performance, and operational excellence; familiarity with TDD, automated testing, and observability stacks.
• Exceptional communication skills with the ability to collaborate across disciplines and levels, from junior engineers to executive leadership.

• Prior experience as a founding or early-stage CTO, Principal Engineer, or Staff+ engineer at a fast-growing startup or open-source project.
• Experience building to production systems in browser automation, AI tooling, or developer infrastructure.
• Knowledge of privacy-preserving technologies, secure computation, or web standards bodies.