Full-Time New Products Principal Engineer

The New Products team at Mozilla is building a browser-automation stack for AI agents. 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.

What you’ll do:

• Technical Strategy & Architecture: Define and communicate the long-term technical roadmap.
• Hands-On Development: Write code daily in languages such as Go, Ruby on Rails, and TypeScript.
• 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.
• Collaboration & Product Direction: Work closely with product, design, and developer-relations to ensure technical choices align with developer needs and business goals.
• Stakeholder Communication: Translate complex technical trade-offs into clear language for executives, partners, and cross-functional teams.

What you’ll bring:

• 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.

Nice to have:

• 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.
• Experience optimizing build systems, WebAssembly pipelines, or cross-language bindings.
• Public speaking or writing history (talks, blogs, whitepapers) explaining complex technical topics to diverse audiences.

What is the last date for applying to the job?

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