Software Engineer, Windows (VPN)

About this role

Build and maintain Proton VPN’s Windows applications, working across the full lifecycle from feature design and implementation to deployment and operational support. The role focuses on privacy-preserving software used by millions, with an emphasis on reliable, well-tested Windows desktop experiences.

About the company

Proton builds end-to-end encrypted email, VPN, storage, password, and related privacy tools for individuals and businesses.

The team

Small Windows VPN team

Stack

What you'll do

• Design, build, maintain, and evolve Proton’s Windows VPN applications
• Contribute to CI/CD, deployment, monitoring, and incident response
• Improve the testing stack, including unit, integration, and automated GUI tests
• Collaborate with product managers and engineers across the company

What we're looking for

• Strong C# and .NET development experience
• Experience building and maintaining Windows desktop applications with WinUI, WPF, or similar
• Understanding of MVVM, dependency injection, async/await, and event-based messaging
• Ability to build maintainable, well-tested, scalable codebases
• Experience leading complex technical projects and driving organizational change
• Understanding of software architecture and engineering best practices
• Working knowledge of TCP/IP, DNS, and routing, with interest in VPN technologies
• Windows debugging, profiling, and performance optimization experience

Nice to have

• Rust experience
• Appreciation for user experience and design quality

Benefits

• Stock options
• Health coverage and retirement options
• Generous leave and wellness support
• Office lunch and snacks
• Public transport, bike, or parking support
• Flexible working hours