OS Integration Engineer, Mac OS Engineering

Company: Mozilla
Location: Elkins Park
Posted on: January 20, 2026

Job Description:

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 this team and role: The OS Integration team ensures Firefox and other Gecko-based products harmonize well with the host operating system and environment. This includes native crash reporting, OS abstraction layers, sandboxing, and hardening. We’re a distributed team with expertise in Windows, macOS, and Linux-based operating systems with this role focusing on macOS. In this role, you will be a member of the OS Integration team specializing in Firefox on macOS. You will primarily work on projects, bug fixes, and enhancements to improve the Firefox user experience on the Mac platform. This will include stability, performance, and security topics as well as implementing support in Firefox for features available on the platform. Projects range from low-level systems programming to user interface components. What you’ll do: • Develop, test, and ship fixes and new features for Firefox on macOS, with a focus on creating a high-quality user experience. • Work in the open source Mozilla codebase touching a variety of technologies including C, C++, rust, Objective-C, JavaScript, and HTML/CSS. • Investigate and respond to crash reports and user-submitted bugs to improve the stability and reliability of Firefox for millions of Mac users. • Grow your expertise while collaborating with a distributed team and participating in technical discussions, planning, code reviews, and problem solving. • Break down problems into manageable units, seek early feedback, and document your design choices to foster learning and alignment. What you’ll bring: • A degree in Computer Science or a related field or comparable work experience. • Demonstrated experience such as a significant project or internship using systems programming languages like C, C++, Objective-C, or Rust. • Ideally, but not required, experience in developing applications for macOS with native frameworks like AppKit or Cocoa. • Knowledge of web technologies such as Javascript, HTML, and CSS. • 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: • Welcoming differences • Being relationship-minded • Practicing responsible participation • Having grit 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 • Quarterly well-being stipend • Considerable paid parental leave • Employee referral bonus program • Other benefits (life/AD&D, disability, EAP, etc. - varies by country)

Keywords: Mozilla, Bayonne , OS Integration Engineer, Mac OS Engineering, IT / Software / Systems , Elkins Park, New Jersey