Senior Software Engineer, OS Integration - Mozilla

About Mozilla

Mozilla Corporation is the non-profit-backed technology company behind Firefox. With more than 225 million people globally using our products each month, we are shaping the next 25 years of technology to build an internet that serves people, not companies. Wholly owned by the non-profit 501(c) Mozilla Foundation, we are beholden only to our mission, designing, building, and distributing open-source software alongside thousands of global contributors.

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 deep expertise across Windows, macOS, and Linux.

Our responsibilities include:

• Developing fixes and improvements for Firefox across Windows, macOS, and Linux environments.
• Integrating with new operating system features and resolving OS-specific UI issues.
• Supporting native crash reporting, OS abstraction layers, sandboxing, hardening, updaters, and enterprise DLP features.

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 this work is cross-platform or contains cross-platform components. This position also includes the maintenance and development of Firefox's installer and updater systems, along with active participation in code reviews and architectural discussions.

What You'll Do

• Debug and fix software defects to enhance product quality and browsing performance for hundreds of millions of users.
• Design and implement new features and cross-platform improvements.
• Break down complex technical tasks and deliver robust solutions collaboratively.
• Conduct rigorous code reviews and provide technical guidance.
• Collaborate across a geographically distributed engineering organization.

What You'll Bring

• 5+ years of professional software engineering experience.
• Strong proficiency in C and C++.
• Practical experience with desktop application development on Windows, macOS, or Linux using C++.
• Familiarity with web standards and technologies (JavaScript, HTML).
• Strong understanding of secure coding practices and memory safety concepts.
• Solid problem-solving and debugging capabilities.
• Excellent written and verbal communication skills for distributed collaboration.

Bonus Points

• Experience developing installers or updaters on any operating system.
• Familiarity with Windows internals (such as BITS or MSIX packages).
• Meaningful contributions to open-source software or personal engineering projects.

What We Offer

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