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# Senior Software Engineer, Firefox Security

- **Company:** Mozilla
- **Location:** France (Remote available)
- **Experience:** Expert
- **Salary:** €53,000.0 - €71,000.0
- **Contract:** Permanent contract
- **Skills:** C++ (Programming Language), Cyber Security, Software Debugging, Memory Management, Cryptographic Protocols, Firefox, Public Key Infrastructure, Software Maintenance, Software Engineering, System Programming, Web Platforms, Multithreading, Web Technologies, Web Api
- **Published:** June 29, 2026
- **Apply:** https://fr.indeed.com/viewjob?jk=138006e8837537a8

## About the Role

* Strong software engineering and security fundamentals: Experience in software engineering, with proficiency in C/C++ and a solid understanding of security principles, including cryptographic protocols and implementations.
 * Experience building and maintaining complex software systems: Ability to contribute to the design, implementation, testing, and maintenance of software in large-scale or security-sensitive environments.
 * Strong debugging and problem-solving skills: Expertise in diagnosing and resolving issues in multi-threaded, cross-platform native applications, including performance and memory-related challenges.
 * Collaborative and effective communicator: Ability to work effectively with distributed teams, communicate technical concepts clearly, and collaborate constructively to solve problems.
 * Growth mindset and willingness to learn: Demonstrated curiosity and desire to deepen expertise in browser security, cryptography, and systems programming while continuously improving engineering skills.
 * Web platform and modern systems experience: Familiarity with web technologies and interest or experience in Rust. Comfortable working within large, complex, multi-language codebases.

## Description

* Advance Firefox's security architecture and cryptography stack: Contribute to improvements in Firefox's core security systems, with a focus on cryptographic protocols, WebPKI, and security-sensitive web APIs. Help implement and maintain security features that support the evolution of public key infrastructure on the web.
 * Design and implement web platform security features: Develop and ship web platform features in collaboration with teammates and the broader web community. Contribute to standards-based, secure, and interoperable implementations across Firefox.
 * Improve browser reliability, performance, and resource efficiency: Investigate and resolve issues impacting stability, correctness, and performance. Analyze and improve memory usage and efficiency within a complex, multi-threaded browser environment.
 * Collaborate on security initiatives: Partner with engineers across teams to identify, prioritize, and address security issues. Participate in debugging, root cause analysis, and implementation of effective long-term solutions.
 * Contribute to technical design and planning: Participate in technical discussions, design reviews, and project planning for security-related initiatives. Help evaluate tradeoffs and contribute to engineering decisions within your area of work.


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