Principal Engineer, Mozilla
New Products
Offers performance-based bonus plans
Internet software for people, not profit
Job no longer available
Internet software for people, not profit
1001+ employees
Job no longer available
Offers performance-based bonus plans
1001+ employees
Company mission
To ensure the internet remains open and accessible.
Role
Who you are
- 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
- 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
Desirable
- 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 the job involves
- 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
- 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
Our take
Mozilla develops a range of free and open-source software, with its most familiar product being Firefox. Operated with a mission-driven, not0for-profit ethos, Mozilla champions online privacy, open standards and user-choice.
Beyond Firefox, Mozilla has focused on privacy forward offerings such as Mozilla VPN, which allows users to browse securely without being tracked. The company has also streamlined its product portfolio to concentrate on initiatives that align closely with its core mission, ensuring resources are dedicated to improving user experiences while fostering safer, more open digital environments.
Alongside this, its impact extends into the developer and tech community, having played a pivotal role in the creation of Rust, a systems programming language celebrated for its speed and efficiency. With a loyal user base, ongoing innovation, and a clear commitment to privacy and open-source principles, Mozilla remains an influential player in the technology landscape.
Freddie
Company Specialist at Welcome to the Jungle
Insights
12% employee growth in 12 months
Company
Funding (last 2 of 3 rounds)
Apr 2018
$1.2m
GRANT
Jan 2005
$0.3m
ANGEL
Total funding: $3.5m
Company benefits
- Health and wellness: Mozilla covers medical, dental and vision plan premiums at 100% for U.S. and Canadian employees. Our offerings give you the options you need to manage your health — and your family’s — the way you want.
- Mental health: Mental health is as important as our physical health. That’s why Mozilla’s health benefits include therapy and coaching sessions to make sure our people have access to the care they need.
- Time away: With all of life’s demands, time away from work to disconnect and recharge is essential. In addition to country-specific holidays (12 in the U.S. and Canada), vacation and sick time start accruing right away (specifics vary by country). Everyone also takes a pause together on quarterly all-company wellness days, plus you get to celebrate the most personal holiday of all: your birthday.
- Parental leave: While Mozilla’s parental leave policies vary globally, our U.S. and Canadian-based employees can look forward to 26 weeks of paid leave for childbearing parents and 12 weeks of paid leave for non-childbearing parents.
- Financial: Mozilla is a private company, so our compensation isn’t tied to stock options or equity plans. Instead, we offer generous, performance-based bonus plans to all regular employees to underscore that we share in our success as one team. As for retirement savings for US and Canadian employees, Mozilla contributes a percentage of your eligible base salary each year to the 401(k) Plan/RRSP (regardless of whether you contribute or not), with 100% vesting.
- Learning and development: We’re big believers in learning by doing, and we also want to invest in your education and development beyond your role. Every employee is eligible for an annual professional development budget. Mozillians can put it toward technical or management training, certifications, conferences and more.
- Help when you need it: Life is full of surprises; that’s why it’s important to be prepared. Mozilla provides Life/AD&D and Short and Long Term Disability insurance (offerings may vary by locale) to ensure that you and your family will have a safety net in place should you ever need it.
- Plus a bit more: A few other benefits include a quarterly wellbeing stipend (to use on those things just for you), an employee referral bonus, internet reimbursement if you’re remote, and a budget for office essentials to make working remotely ergonomically comfortable.
Company HQ
Rincon Hill, San Francisco, CA
Leadership
Laura Chambers
(CEO)Alongside serving as the CEO at Mozilla, Laura is an Executive Fellow at Harvard Business School. Previously, she was the CEO and PResident at Willow Innovation, Director at Patelco Credit Union, and General Manager of Core Hosts & Community at Airbnb.
Share this job
View 65 more jobs at Mozilla