Senior Software Engineer

Work on security and hardening features for Firefox, including privilege isolation, trust boundaries, cryptographic protocols, and WebPKI. Design, build, test, and ship security and hardening features, including for enterprise users. Strengthen Firefox's security architecture across operating systems. Improve core mechanisms such as cryptographic protocols, WebPKI, and security-sensitive web APIs. Investigate security issues, find root causes, and deliver lasting fixes. Diagnose stability, performance, and memory issues in a multithreaded codebase.

• 3+ years in low-level software engineering, with strong C and/or C++
• Solid understanding of security fundamentals
• Debugging experience in multithreaded, cross-platform native applications
• Familiarity with web technologies (HTML, CSS, JavaScript), and interest or experience in Rust
• Ability to work in large, multi-language codebases
• Clear written and verbal communication with distributed teams

• Performance-based bonus plans
• Retirement contributions with 100% immediate vesting
• Quarterly company-wide wellness days and a birthday day off
• One-time home office stipend, annual professional development budget, and quarterly wellbeing stipend
• Considerable paid parental leave and an employee referral bonus