Senior Software Engineer, OS Integration - Mozilla

About the OS Integration Team

The OS Integration team ensures Firefox works seamlessly with host operating systems and desktop environments. We are a distributed team with expertise across Windows, macOS, and Linux-based systems.

Our responsibilities include developing fixes and enhancements for Firefox related to OS environments, integrating new OS features, resolving platform-specific UI issues, native crash reporting, OS abstraction layers, sandboxing, hardening, installer/updater systems, and enterprise DLP support.

About the Role

As a Senior Software Engineer on the OS Integration team, you will develop fixes, improvements, and new features for Firefox. Much of your work will be cross-platform or feature cross-platform components, including maintenance and development of Firefox’s installer and updater. You will also contribute through architecture discussions and peer code reviews.

What You'll Do

• Improve the quality of Firefox and other Mozilla products by debugging and fixing defects for hundreds of millions of users.
• Design and contribute to new features, platform integrations, and cross-platform improvements.
• Break down complex technical tasks and collaborate across teams to deliver robust solutions.
• Perform code reviews and provide technical guidance within a geographically distributed engineering team.
• Collaborate with teams across Mozilla to align on OS-level capabilities and platform architecture.

What You'll Bring

• 5+ years of software engineering experience.
• Strong proficiency in C and C++.
• Proven experience in desktop application development on Windows, macOS, or Linux using C++.
• Familiarity with web technologies, including JavaScript and HTML.
• Strong understanding of secure coding practices and memory safety considerations.
• Proven problem-solving and debugging capabilities.
• Effective written and verbal communication skills tailored for a distributed team.

Bonus Points

• Experience building installers or updaters on any operating system.
• Familiarity with Windows internals, such as the BITS service or MSIX packaging.
• Track record of open-source contributions or personal systems engineering projects.

What You'll Get

• Performance-based bonus program.
• Comprehensive medical, dental, and vision coverage.
• Generous retirement contributions with 100% immediate vesting.
• Quarterly all-company wellness days.
• Country-specific public holidays plus a day off for your birthday.
• One-time home office setup stipend.
• Annual professional development budget.
• Substantial paid parental leave.
• Employee referral bonuses and life/disability coverage.

About Mozilla

Mozilla exists to build the Internet as a public resource accessible to all. Wholly owned by the non-profit 501(c) Mozilla Foundation, we are beholden only to our mission—not shareholders. Mozillians design, build, and distribute open-source software that empowers people around the globe.