Senior Software Engineer, Privacy - Mozilla

About Mozilla

Mozilla Corporation is the non-profit-backed technology company that has shaped the internet for the better over the last 25 years. We build pioneering products like Firefox, the privacy-minded web browser. Today, more than 225 million people globally rely on our products each month. Wholly owned by the non-profit 501(c) Mozilla Foundation, we are not beholden to shareholders—only to our mission to keep the internet open, accessible, and centered around people.

About the Role & Team

Mozilla is seeking a Senior Software Engineer to support our Privacy Team in advancing the Firefox Web Platform. In this role, you will implement privacy-improving technologies, anti-tracking mechanisms, and architectural enhancements directly into Gecko, the browser engine underlying Firefox.

What You'll Do

• Implement privacy-improving, anti-tracking, and threat intelligence protections in Firefox to mitigate user tracking and phishing.
• Implement architectural improvements within Gecko, the browser engine underlying Firefox.
• Write performant, low-latency, and maintainable C++, JavaScript, and Rust code.
• Collaborate as part of a geographically distributed, asynchronous team (primarily Europe and US-East).

What You'll Bring

• Bachelor's degree in Computer Science, Engineering, or a related field; or equivalent practical experience.
• At least 4 years of experience programming in C++ and Rust, with strong expertise in memory safety, multi-threaded system architecture, or raw data stream manipulation.
• Proven track record of independently scoping and landing complex features within tight release windows.
• Demonstrated ability to onboard quickly, deliver high-quality code, and improve complex software projects.
• Excellent written and verbal communication skills, with the ability to validate and articulate technical decisions clearly.

Bonus Points

• Prior contributions to the Mozilla mission and codebase.
• Experience working within the browser space (Gecko, Chromium, WebKit) or web engine runtime abstractions.
• Experience or interest in designing or leveraging ML pipelines to automate developer workflows.
• Deep understanding of web architecture, the privacy/security model of the web, and client-side data structures.
• Knowledge of basic statistical modeling.
• Proficiency with Python and SQL.

Benefits & Perks

• Performance-based bonus plans for all eligible employees
• Generous retirement contributions with 100% immediate vesting
• Quarterly all-company wellness days
• Country-specific paid holidays plus a day off for your birthday
• One-time home office setup stipend
• Annual professional development budget
• Quarterly well-being stipend
• Generous paid parental leave
• Employee assistance program (EAP) and life/disability coverage