Senior Software Engineer, OS Integration

Mozilla; Toronto; On-site; CAD 104,000 - 139,000; Full time

Benefits offered by this job

Generous bonus plans

Medical, dental, and vision coverage

Retirement contributions with vesting

Home office stipend

Professional development budget

Parental leave

Employee referral bonus

Job summary

Mozilla Corporation’s OS Integration team seeks a seasoned software engineer to develop fixes and features for Firefox across Windows, macOS, and Linux. You’ll help maintain the installer and updater, contribute to cross-platform improvements, and review code with a distributed team.

Ideal candidates have 5+ years of software engineering, deep C/C++ knowledge, desktop app experience on major OSes, and strong debugging and collaboration skills.

Qualifications

• 5+ years of software engineering experience.
• Strong knowledge of C and C++.
• Experience with desktop app development on Windows, macOS, or Linux with C++.
• Knowledge of 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 Mozilla values.

Responsibilities

• Improve Firefox quality by debugging and fixing defects.
• Contribute to new features and improvements.
• Break down tasks and collaborate to deliver solutions.
• Perform code reviews and provide technical direction.
• Work with a geographically-distributed development team.
• Interact with teams throughout the organization.

Skills

C and C++

Desktop C++

JavaScript

HTML

Problem solving

Communication

Distributed team

Tools

Windows internals

BITS server

MSIX packages

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 privileges of employment, as appropriate. Please contact us at [e-mail] 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.

Hiring Ranges

Canada Tier 1 Locations

$104,000—$139,000 CAD

Canada Tier 2 Locations

$95,000—$126,000 CAD