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# software engineer

- **Company:** Mozilla Corporation
- **Location:** Madrid, Spain (Remote available)
- **Salary:** €75,000.0 - €100,000.0
- **Contract:** Permanent contract
- **Skills:** Clean Code Principles, JavaScript (Programming Language), Microsoft Windows, Android Software Development, Apple IOS, Apple Mac Systems, C++ (Programming Language), Code Review, Software Debugging, Linux, Virtual Private Networks (VPN), Python (Programming Language), Network Protocols, Qt (Software), Software Engineering, Tcpdump, Wireshark, TypeScript, VPN Clients, Git, Free and Open-Source Software, Golang
- **Published:** July 21, 2026
- **Apply:** https://www.adzuna.es/contact-us.html

## About the Role

6+ years of software engineering experience
Expert level proficiency in C/C++
Expertise in networking protocols and privacy and security best practices
Extensive knowledge of core OS concepts of Windows or Mac
Experience developing cross-platform applications (Windows, macOS, Linux, iOS, Android)
Experience debugging network related problems with Wireshark, tcpdump, or similar tools
Excellent communication skills and experience mentoring engineers
Bonus points:
Experience developing cross platform applications with Qt
Proficiency in any of the following: Rust, Go, Python, Javascript, TypeScript, Git
Open-source contributions to networking or VPN-related projects
Experience implementing or improving application observability

## Description

Mozilla VPN is seeking an experienced software engineer to join our fully remote, global engineering team. In this role, you will contribute to the suite of products that make up the Mozilla VPN project, including browser extensions, browser integrations, and the Mozilla VPN client-a cross-platform application available on Windows, macOS, Linux, iOS, and Android. You will be responsible for implementing new features as well as improving the performance and the reliability of existing functionality. Additionally, you will have the opportunity to be at the forefront of innovative, challenging, and technically complex initiatives.
What you'll do:
Drive the architecture, development, and optimization of the Mozilla VPN client across platforms (Windows, macOS, Linux, iOS, Android).
Work closely with cross functional colleagues, providing technical insight to drive feature development.
Maintain high-quality code, enforce security best practices, and mentor engineers by providing comprehensive and insightful code reviews.
Triage, debug and resolve software defects


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