Senior Software Engineer, Firefox Security

• Advance Firefox's security architecture and cryptography stack, contributing to improvements in core security systems including cryptographic protocols, WebPKI, and security-sensitive web APIs. • Design and implement web platform security features in collaboration with teammates and the broader web community, contributing to standards-based, secure, and interoperable implementations. • Investigate and resolve issues impacting browser stability, correctness, performance, and memory efficiency within a complex, multi-threaded environment. • Partner with engineers across teams to identify, prioritise, and address security issues through debugging, root cause analysis, and long-term solutions. • Work fully remotely from the UK, Spain, Germany, Sweden, France, Finland, Belgium, or the Netherlands.

• Bring strong software engineering and security fundamentals, with proficiency in C/C++ and a solid understanding of security principles including cryptographic protocols and implementations. • Bring experience contributing to the design, implementation, testing, and maintenance of software in large-scale or security-sensitive environments. • Bring expertise in diagnosing and resolving issues in multi-threaded, cross-platform native applications, including performance and memory-related challenges. • Bring familiarity with web technologies and interest or experience in Rust, with comfort working within large, complex, multi-language codebases. • Bring strong collaborative and communication skills, with the ability to work effectively with distributed teams and explain technical concepts clearly.

• Bring deeper expertise in browser security, WebPKI, or public key infrastructure on the web. • Bring hands-on experience with Rust in a production environment. • Bring experience contributing to web platform standards or cross-browser security initiatives. • Bring a history of contributions to open source projects, particularly in browser or systems programming contexts.

• Contribute to improvements in Firefox's core security systems, with a focus on cryptographic protocols, WebPKI, and security-sensitive web APIs. • Develop and ship web platform security features in collaboration with teammates and the broader web standards community. • Investigate and resolve issues impacting browser stability, correctness, and memory efficiency across platforms. • Participate in technical discussions, design reviews, and project planning for security-related initiatives, helping evaluate tradeoffs and contributing to engineering decisions. • Partner with engineers across teams to identify and prioritise security issues, contributing to debugging and long-term remediation.

• Receive generous performance-based bonus plans shared across the team. • Access rich medical, dental, and vision coverage, plus generous retirement contributions with 100% immediate vesting. • Take considerable paid parental leave and a day off for your birthday, plus quarterly all-company wellness days. • Receive a one-time home office stipend, an annual professional development budget, and a quarterly wellbeing stipend. • Benefit from an employee referral bonus programme and additional benefits including life, AD&D, disability, and EAP cover.

Mozilla Corporation is the non-profit-backed technology company behind Firefox, used by more than 225 million people monthly. Wholly owned by the Mozilla Foundation, Mozilla builds open-source software that enables people to enjoy the internet on their own terms — never beholden to shareholders, always focused on making the internet better for people.