Senior Software Engineer, DOM: Workers & Storage Team
at Mozilla Corporation
Berlin Office, Remote Germany

The Role

The DOM: Workers & Storage team at Mozilla has a long name but its mission is simple: provide excellent implementations in Firefox of the standardized localStorage, Cache API, IndexedDB, Web Worker, and Service Worker APIs. Web developers whose work is rendered by Firefox’s engine, 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? 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!

Opportunities to collaborate with other browser teams abound, and working in the open is the norm. Firefox is a mature project always looking for new optimizations, and we are trying to write some of our new components in Rust. You’ll be responsible for writing code, tests, specifications, building prototypes, solving problems, and analyzing data. You'll get feedback from real users and synthesize it into bug reports, feature designs, and strategic direction to make the web platform even better over time.

In this role you will:

  • Increase Firefox’s web browsing speed and responsiveness.
  • Debug and fix problems in our multi-threaded codebase.
  • Improve Firefox’s stability and correctness.
  • Analyze and reduce Firefox’s memory usage.
  • Design and implement new web platform features in collaboration with the web community.
  • Work cooperatively with other Mozillians to identify and correct issues.

Your professional profile:

  • Proficient with C++.
  • Creative problem-solver and skilled debugger and profiler.
  • Experience working on a cross-platform native application.
  • Ability to learn a large and complex multi-language code base.
  • Excellent written and verbal communication skills.
  • Familiarity with the modern web platform is a plus.
  • Experience designing and building APIs would make you stand out.

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.

Commitment to diversity, equity, inclusion, and belonging

Mozilla understands that valuing diverse creative practices and forms of knowledge are crucial to and enrich the company’s core mission.  We encourage applications from everyone, including members of all equity-seeking communities, such as (but certainly not limited to) women, racialized and Indigenous persons, persons with disabilities, persons of all sexual orientations, gender identities and expressions.

We will ensure that qualified individuals with disabilities are provided reasonable accommodations to participate in the job application or interview process, to perform essential job functions, and to receive other benefits and privileges of employment, as appropriate. Please contact us at to request accommodation.

We are an equal opportunity employer. We do not discriminate on the basis of race (including hairstyle and texture), religion (including religious grooming and dress practices), gender, gender identity, gender expression, color, national origin, pregnancy, ancestry, domestic partner status, disability, sexual orientation, age, genetic predisposition, medical condition, marital status, citizenship status, military or veteran status, or any other basis covered by applicable laws.  Mozilla will not tolerate discrimination or harassment based on any of these characteristics or any other unlawful behavior, conduct, or purpose.

Group: D


Why Mozilla?

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

  • 700+ paid staff from over 30 countries
  • Thousands of volunteer contributors across six continents
  • 9 global offices: Mountain View, San Francisco, Portland, Vancouver, Toronto, Paris, London, Berlin, and Beijing
  • 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