Senior Security Software Engineer (Remote France)

Mozilla; Paris; Remote; EUR 53,000 - 71,000; Full time

Benefits offered by this job

Performance bonus

Retirement contributions

Wellness days

Birthday day off

Home office stipend

Professional development budget

Parental leave

Employee referral bonus

Life/AD&D

Disability insurance

EAP

Job summary

Mozilla is seeking a security-focused systems programmer to design, build, and ship enterprise-grade security features for Firefox across multiple operating systems. You will advance Firefox’s security architecture and contribute to cryptographic, WebPKI and security-sensitive APIs while collaborating with distributed teams.

Join Mozilla to improve browser reliability, performance, and security posture, with a focus on strong code quality and scalable engineering practices.

Qualifications

• Systems programming experience and security knowledge: 3+ years of experience in low-level software engineering, strong proficiency in C and/or C++, and a solid understanding of security fundamentals.
• Debugging and problem-solving skills: Experience diagnosing issues in multithreaded, cross-platform native applications, including memory and performance challenges.
• Web platform and modern systems experience: Familiarity with web technologies (HTML, CSS, JavaScript) and interest or experience in Rust; ability to work in large, multi-language codebases.
• Effective collaboration and communication: Experience working with distributed teams and communicating technical ideas clearly.

Responsibilities

• Design, build and implement security and hardening features for enterprise users across Firefox.
• Advance Firefox’s security architecture across multiple operating systems and improve core security mechanisms.
• Contribute to security initiatives: investigate issues, identify root causes, and deliver fixes.
• Improve browser reliability and performance: diagnose and resolve issues affecting stability and memory usage.

Skills

3+ years systems programming

C and/or C++

security fundamentals

multithreaded debugging

web technologies (HTML, CSS, JS)

Rust interest/experience

distributed teamwork

clear written and verbal communication

Job description

Mozilla is seeking a security-focused systems programmer to design, build, and ship enterprise-grade security features for Firefox across multiple operating systems. You will advance Firefox’s security architecture and contribute to cryptographic, WebPKI and security-sensitive APIs while collaborating with distributed teams.

Join Mozilla to improve browser reliability, performance, and security posture, with a focus on strong code quality and scalable engineering practices.