66K–87K GBP / year
Senior Software Engineer, Firefox Security
OtherRemote — UK
Published on 2026-10-14
These details were extracted automatically from the original listing. They may not be complete or fully up to date — it's worth checking the original job post.
About this role
Build and ship security features that strengthen Firefox for enterprise users. Improve Firefox’s security architecture across operating systems while addressing reliability, performance, and memory challenges in a complex, multithreaded codebase.
About the company
Mozilla builds open-source products and technologies, including Firefox, that prioritize privacy, security, and an open internet.
Stack
CC++RustHTMLCSSJavaScript
What you'll do
- Design, implement, test, and ship Firefox security and hardening features
- Improve privilege isolation and security boundaries across operating systems
- Strengthen security mechanisms, including cryptographic protocols, WebPKI, and security-sensitive web APIs
- Investigate security issues, find root causes, and deliver maintainable fixes
- Diagnose stability, correctness, performance, and memory issues
What we're looking for
- 3+ years of low-level software engineering experience
- Strong proficiency in C and/or C++ and understanding of security fundamentals
- Experience debugging multithreaded, cross-platform native applications
- Familiarity with web technologies and ability to work in large, multi-language codebases
- Clear written and verbal communication and experience working with distributed teams
Nice to have
- Interest or experience in Rust
Benefits
- Performance-based bonus plan
- Retirement contributions with immediate vesting
- Quarterly company wellness days
- Country-specific holidays and a birthday day off
- One-time home-office stipend
- Annual professional development budget
- Quarterly well-being stipend
- Paid parental leave