MozillaHiring

Senior Software Engineer, Firefox Security

  • Remote, Netherlands
  • Senior
  • Posted 2 weeks ago
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In one line

Security engineering role on a browser team, hardening the browser for enterprise users in C++ and Rust; remote-friendly within a distributed org.

About the role

The team works on privilege isolation, trust boundaries and core security mechanisms such as cryptographic protocols and WebPKI. Fixes have to hold up in a large, multithreaded codebase used by millions.

At a glance

Pay
Not stated in the posting
Remote scope
Remote, Netherlands
Seniority
Senior
Skills
Rust, HTML, CSS, JavaScript, WebPKI, Cryptographic protocols
Posted
15 Oct 2026
Last checked
28 Oct 2026

What you will do

  • Design, test and ship security and hardening features for enterprise users
  • Improve core security architecture across operating systems, including privilege isolation and trust boundaries
  • Investigate security issues across teams, find root causes and deliver maintainable fixes
  • Diagnose stability, correctness, performance and memory problems in multithreaded native code

What they look for

  • Three or more years in low-level systems programming
  • Strong C or C++ skills and a solid grasp of security fundamentals
  • Experience debugging cross-platform, multithreaded native applications
  • Familiarity with HTML, CSS and JavaScript, plus interest in Rust

Nice to have

  • Experience working in large, multi-language codebases
  • A track record of communicating technical ideas in writing across distributed teams

Benefits

  • Performance-based bonus plans and retirement contributions with immediate vesting
  • Home office stipend, professional development budget and paid parental leave

How Keywordise applies for you

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Claude

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Connector URL
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ChatGPT

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Connector URL
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Muse

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Message for Muse
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Muse is available in the US only for now.

Prompt
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How to connect

Questions about this job

Can I do this job remotely, and from which countries?

Yes, it is listed as remote, aimed at candidates in the Netherlands.

What does this job pay?

The posting does not state a salary, so there is no figure to quote.

What experience is needed?

It is a senior role. The posting asks for: three or more years in low-level systems programming; strong C or C++ skills and a solid grasp of security fundamentals; experience debugging cross-platform, multithreaded native applications. Skills it names include Rust, HTML, CSS, JavaScript.

How do I apply with Keywordise AI?

Click Apply with Keywordise AI, create an account and upload your CV. Your CV and cover letter are written for this job from what you have really done, then Keywordise applies for you. Trial: 7 days, no card.

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