Staff Software Engineer - Windows Platform
at Mozilla Corporation
Core Product-Firefox
Berlin Office, Toronto Office, Remote US, Remote Canada, Remote Germany, Remote UK, Remote France

The OS integration team is a cross-disciplinary team in charge of improving and maintaining Firefox on its various supported operating systems. We make sure Firefox is a first-class citizen that integrates well with the desktop and supports new features offered by the operating system. 

Firefox is a complex cross-platform application and we deal with the operating system specifics. We work on crash reporting, interactions with third party software, sandboxing, hardening techniques, and investigating crashes. We develop close to the machine on low-level topics such as browser performance, security, Inter Process Communication (IPC), memory allocators, and power usage.

This role on the OS integration team will focus on Firefox on the Windows platform.

As a Staff Software Engineer in OS integration you will:

  • Improve the quality of Firefox by debugging and fixing software defects, improving the browsing experience for hundreds of millions of users.
  • Investigate Firefox problems caused by interactions with third party software products, especially DLL injection.
  • Lead projects that improve the stability, security, and performance of Firefox.
  • Collaborate with experienced software engineers.
  • Further develop your understanding of the Windows platform.
  • Perform code reviews and provide technical direction.
  • Work with a geographically-distributed development team.
  • Interact with teams throughout the organization.

You should have:

  • A solid understanding of C, C++, and x86 and x64 assembly language.
  • Experience with low-level systems programming on Windows.
  • The ability to learn fast and figure out things independently, but know when to stop and ask for help or feedback.
  • Excellent communication skills with a history of working effectively on a geographically distributed team.
  • General web development knowledge.

Bonus points if you have:

  • Low-level Win32 API coding experience.
  • Low-level systems programming experience on another operating system.
  • Kept up to date with major language changes (C++11 and beyond) and best practices.
  • Programming experience in Rust.
  • Previously contributed to an open source project.

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: C


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