Senior Software Engineer, OS Integration

Mozilla; Town of Belgium (WI); Hybrid; USD 130,000 - 190,000; Full time

Benefits offered by this job

Bonus plans

Medical, dental, and vision coverage

Retirement contributions

Home office stipend

Professional development budget

Parental leave

Employee referral bonus

Life/AD&D and disability benefits

Job summary

Mozilla OS Integration engineers ensure Firefox runs smoothly on Windows, macOS and Linux, developing fixes, improvements and installer/updater features in a cross‑platform context. You will participate in code reviews to shape technical direction and collaborate with teammates across Mozilla.

You’ll apply strong C/C++ skills, secure coding practices, and memory-safety awareness to deliver reliable software for hundreds of millions of users while contributing to a distributed engineering culture.

Qualifications

• 5+ years of software engineering experience
• Strong knowledge of C and C++
• Experience with desktop application development on Windows, macOS, or Linux with C++
• Knowledge of web technologies such as JavaScript and HTML
• Secure coding practices and memory safety awareness
• Strong debugging and problem-solving skills
• Clear written and verbal communication with a collaborative mindset

Responsibilities

• Improve Firefox and Mozilla products by debugging and fixing defects to enhance user experience
• Contribute to new features and cross-platform improvements
• Break down tasks and collaborate to deliver solutions
• Participate in code reviews and provide technical direction
• Work with a distributed development team across the organization
• Interact with teams throughout Mozilla

Skills

C/C++

Desktop app development

Javascript/HTML

Problem solving

Distributed teamwork

Code reviews

Secure coding

Tools

Windows internals

MSIX/BITS

Job description

Why Mozilla?

Mozilla Corporation is the non-profit-backed technology company that has shaped the internet for the better over the last 25 years. We make pioneering brands like Firefox, the privacy-minded web browser. Now, with more than 225 million people around the world using our products each month, we’re shaping the next 25 years of technology and helping to reclaim an internet built for people, not companies. Our work focuses on diverse areas including AI, social media, security and more. And we’re doing this while never losing our focus on our core mission – to make the internet better for people. The Mozilla Corporation is wholly owned by the non-profit 501(c) Mozilla Foundation. This means we aren’t beholden to any shareholders — only to our mission. Along with thousands of volunteer contributors and collaborators all over the world, Mozillians design, build and distribute open-source software that enables people to enjoy the internet on their terms.

About the OS Integration team:

The OS Integration team ensures Firefox works well with the host operating system and environment. We’re a distributed team with expertise in Windows, macOS, and Linux-based operating systems. Our responsibilities include developing fixes and improvements for Firefox related to Windows, macOS, and Linux environments. This might include integration with a new OS feature or fixing an OS-specific user interface bug. Other responsibilities include native crash reporting, OS abstraction layers, sandboxing, hardening, updater, and enterprise DLP support.

About the role:

As a member of the OS Integration team, you’ll develop fixes, improvements, and new features for Firefox. In many cases work may be cross-platform or have a cross-platform component. This role will include maintenance and development of the installer and updater of Firefox. You’ll contribute to the team through code review and discussion.

What you’ll do:

• Improve the quality of Firefox and other Mozilla products by debugging and fixing software defects, improving the browsing experience for hundreds of millions of users.
• Contribute to new features and improvements.
• Break down tasks and work with others to deliver solutions.
• Collaborate with experienced software engineers.
• Perform code reviews and provide technical direction.
• Work with a geographically-distributed development team.
• Interact with teams throughout the organization.

What you’ll bring:

• 5+ years of overall software engineering experience
• Strong knowledge of C and C++
• Experience with desktop application development on Windows, macOS, or Linux with C++
• Knowledge of web technologies such as Javascript and HTML
• Knowledge of secure coding practices and memory safety concerns
• Strong problem-solving and debugging skills
• Written and verbal communication skills with a collaborative mindset
• Willingness to work effectively in a distributed team environment.

Commitment to our values:

Play to win Build for People first Engage Evidence over Ego Decide and Deliver Ship, learn and repeat

Bonus Points for experience with:

• Installer and/or Updater development on any OS
• Windows internals like the BITS server or MSIX packages
• Open-source contributions or personal engineering projects

What you’ll get:

• Generous performance-based bonus plans to all eligible employees - we share in our success as one team
• Rich medical, dental, and vision coverage
• Generous retirement contributions with 100% immediate vesting (regardless of whether you contribute)
• Quarterly all-company wellness days where everyone takes a pause together
• Country specific holidays plus a day off for your birthday
• One-time home office stipend
• Annual professional development budget
• Considerable paid parental leave
• Employee referral bonus program
• Other benefits (life/AD&D, disability, EAP, etc. - varies by country)

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