New Products Principal Engineer

Shape the Future of AI with Mozilla: Principal Software Engineer

For 25 years, Mozilla has been a driving force behind a better internet, championing privacy and open-source technology. We’re more than just Firefox – we’re a non-profit-backed organization committed to building an internet that puts people first. Join us as we shape the next 25 years of the web, focusing on crucial areas like AI, social media, and security, all while staying true to our core mission.

We’re on the lookout for a visionary Principal Software Engineer to join our New Products team and spearhead the development of a cutting-edge browser-automation stack for AI agents. This is a unique opportunity to be a founding member and directly impact the future of how developers integrate fast, reliable web interactions into their AI applications.

About the Team & the Role

The New Products team is a nimble, innovative group focused on empowering developers with tools they’ll love. As our Principal Software Engineer, you will:

• Lead the Technical Vision: Define and communicate the long-term technical roadmap for our browser-automation stack, balancing rapid iteration with scalability.
• Drive Hands-On Development: Write clean, high-performance code daily, using languages like Go, Ruby on Rails, and TypeScript. Prototype and ship features quickly.
• Architect Systems & Infrastructure: Design distributed, fault-tolerant services and intuitive developer-facing SDKs/APIs. Own our cloud infrastructure, CI/CD pipelines, security, and observability.
• Mentor & Inspire: Cultivate a world-class engineering team by providing guidance, conducting thoughtful code reviews, and fostering a culture of technical excellence and psychological safety.
• Collaborate & Steer Product Direction: Work closely with product, design, and developer relations to ensure our technical choices align with developer needs and business goals. Translate community feedback into tangible improvements.
• Communicate Effectively: Translate complex technical trade-offs into clear, concise language for executives, partners, and cross-functional teams. Keep stakeholders informed about progress, risks, and mitigation strategies.

What You’ll Bring to the Table

We’re looking for someone who is passionate about building exceptional developer tools and has a proven track record of success. Here’s what we’re looking for:

• 10+ years of software engineering experience, with at least 3 years leading technical teams or large projects, building high-performance developer tools, SDKs, or distributed systems.
• Expert-level proficiency in at least two of the following: Go, Ruby (Rails), Python, or TypeScript/JavaScript.
• Demonstrated experience architecting and deploying 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 with modern AI/ML workflows or agent frameworks (e.g., LangChain, LlamaIndex, or custom in-house systems).
• A strong commitment to code quality, testability, performance, and operational excellence; familiarity with TDD, automated testing, and observability stacks.
• Exceptional communication and collaboration skills, with the ability to work effectively across disciplines and levels.

Bonus Points

These are great additions to your skill set:

• 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 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.

Why Choose Mozilla?

Mozilla is more than just a job; it’s a mission. We offer a unique environment where you can:

• Contribute to a globally recognized organization that prioritizes people over profit.
• Work on cutting-edge technologies that are shaping the future of the internet.
• Collaborate with a passionate and talented team of engineers and innovators.
• Enjoy a comprehensive benefits package, including:
  • Generous performance-based bonus plans
  • Rich medical, dental, and vision coverage
  • Generous retirement contributions with immediate vesting
  • Quarterly all-company wellness days
  • Country-specific holidays plus a birthday day off
  • Home-office stipend
  • Annual professional development budget
  • Quarterly well-being stipend
  • Paid parental leave
  • Employee referral bonus program
  • Other benefits (life/AD&D, disability, EAP, etc.)

At Mozilla, we embrace diversity, equity, inclusion, and belonging. We encourage applications from all equity-seeking communities. We are committed to providing reasonable accommodations to qualified individuals with disabilities.

Join the Mozilla Movement

Help us build a better internet, one line of code at a time. Apply now to become our Principal Software Engineer and be a part of something truly meaningful.

Hiring Ranges:

US Tier 1 Locations: $216,000—$288,000 USD

US Tier 2 Locations: $199,000—$265,000 USD

US Tier 3 Locations: $184,000—$245,000 USD

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