Why join Mozilla engineering?

Learn: Code review at Mozilla includes pushing to passionate contributors around the world. Building Firefox and its family of products requires knowledge up and down the stack, and extremely high standards for security and optimization. Beyond the browser, we’re developing AR/VR, IoT, and voice recognition products that respect and protect privacy.

Grow: We’re dedicated to helping every team member develop. We give engineers trust and responsibility from day one, offer generous stipends for learning opportunities, and provide mentorship, especially around key leadership skills like collaboration and clear, kind communication.

Make Your Mark: We’re small but mighty, challenging the biggest behemoths on the internet with a staff the size of their marketing departments. That means every engineer can have an outsized impact on products that touch tens of millions of users—ultimately influencing how the entire internet works.

The Role

The DOM: Core team at Mozilla is responsible for many features of Firefox’s high-performing Web rendering engine, Gecko. We aim for intelligent hardware utilization, excellent user interaction and Web compatibility while we push the boundaries of what the Web is capable of. We do this by delivering outstanding implementations in Firefox of the standardized APIs, such as HTML, Events, Editor, and so on. Web developers whose work is rendered by Gecko rely on these implementations for building modern Web experiences. Firefox itself also uses these technologies! The team works together to enhance our existing implementations and with the broader Web community to advance the capabilities of these standardized APIs.


Is debugging multi-threaded C++ code a challenge you love? Do you feel excited about improving Web text editing and advancing its features? How about improving the performance of an API that is used by top websites so that millions of Firefox users benefit? If you’re also enthusiastic about working collaboratively with a worldwide community, we'd love to hear from you.


As a Firefox DOM Editor engineer, you’ll be responsible for:

  • Working cooperatively with other Mozillians to identify and correct issues, and asking for help as needed.
  • Providing excellent text editing experiences to users who speak different languages or use IMEs (input method editors).
  • Ensuring Firefox complies with Web Standards and works with real websites.
  • Increasing Firefox’s Web browsing speed and responsiveness.
  • Analyzing and helping reduce Firefox’s memory usage.

Your professional profile:

  • Capable C++ programmer.
  • Motivated to learn new tools and techniques for improving existing software.
  • Familiarity with one or more of the following will help you stand out:
    • Multi-threaded code.
    • Debugging and performance profiling.
    • The modern Web platform.

Nice to have:

  • Experience with or knowledge about IMEs (input method editors).


An interest in learning new techniques, tools, and skills with a curiosity to read lots of existing code is essential to success. You will pair with local mentors while working with a distributed team and the worldwide Mozilla community. There will be some travel for working face-to-face with colleagues and career growth through conferences. Continuous learning opportunities will be provided.

Feel good about your work again.

At Mozilla, we’re serving humanity—by maintaining a safe, open internet—while also helping the individual humans employed here to reach their personal and professional goals. With a relatively small team serving hundreds of millions of people, a culture of exploration, and a commitment to mentorship, opportunities abound to learn and grow at Mozilla.

Our values drive our actions

  • Purpose is built into our work, with our mission driving every decision
  • We challenge assumptions, the status quo, ourselves, and each other
  • We are transparent: in our code, our business partnerships, and our everyday interactions 
  • We seek out people from diverse backgrounds and with perspectives different from our own 
  • We pair purpose with performance and put people ahead of profit

Our impact is global

  • 1000+ paid staff from over 30 countries
  • Thousands of volunteer contributors across six continents
  • 10 global offices: Beijing, Berlin, London, Paris, Mountain View, Portland, San Francisco, Taipei, Toronto and Vancouver
  • Hundreds of home offices globally

Our benefits are world-class 

  • Flexible work environment (nearly half of Mozillians work remotely)
  • Industry-leading paid parental leave (up to 26 weeks of fully paid leave for childbearing parents and up to 12 weeks for non-childbearing parents)
  • Reimbursement for professional development (up to $3,000/year)
  • A work setup including the latest hardware and software of your choice
  • Wellness programs—we reimburses up to $1700/year for expenses like child and elder care, mental wellness, and personal enrichment 

About Mozilla

Mozilla exists to build the Internet as a public resource accessible to all because we believe that open and free is better than closed and controlled. When you work at Mozilla, you give yourself a chance to make a difference in the lives of Web users everywhere. And you give us a chance to make a difference in your life every single day. Join us to work on the Web as the platform and help create more opportunity and innovation for everyone online.

We are an equal opportunity employer and value diversity. We do not discriminate on the basis of race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status.

A lot of companies say they’re “mission-driven.” Our unique corporate structure guarantees that every decision we make upholds our mission: to make sure the internet stays available, safe, and welcoming to everyone. Beholden to neither shareholders nor investors, Mozilla Corporation is wholly owned by the not-for-profit Mozilla Foundation.

Along with 20,000+ volunteer contributors and collaborators all over the world, Mozilla Corporation’s staff designs, builds, and distributes software that allows people to enjoy the internet on their own terms. Our flagship product — the Firefox browser — has expanded into a family of products that protects users and alerts them of risks. Mozilla’s Emerging Technologies group incubated and sponsors Rust — Stack Overflow’s “most loved programming language” for the last four years — and is building safe, private versions of virtual reality, internet of things, and voice recognition.


Group: E


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