Software Engineer, Windows (VPN)

Strong experience building and maintaining Windows desktop applications using frameworks such as WinUI, WPF, or similar.

Solid understanding of MVVM architecture, dependency injection, asynchronous programming (async/await), and event‑based messaging patterns.

Proven ability to write maintainable, well‑tested, and scalable codebases.

A strong understanding of software architecture and engineering best practices.

An appreciation for user experience and design quality.

Rust experience is not required but is a significant plus.

Office First: Collaboration is easier and more effective in person, which is why we have offices in Geneva, Zurich, Prague, Barcelona, Paris, London, Vilnius, Skopje, and Taipei. You can also enjoy working from home up to 30% of the time, while enjoying great company during our three core days in the office.

Technology: We provide all the devices and software you need to excel in your role, ensuring you have the best tools at your disposal to achieve your goals.

Food: Lunch and snacks are provided by Proton every day at our offices.

Transport: We will always support our employees with transport costs through subsidizing public transport, bike allowances, or parking spaces based on your office location.

Stock Options: At Proton, we are all owners of the company and you get stock options when you join us.

Flexible Working: You can define your own working hours as long as it works with team meetings.

As an engineer on our small Windows VPN team, you will be responsible for designing, building, maintaining, and evolving Proton’s applications on Windows.

You will be involved in the entire application lifecycle, from feature design and implementation to CI/CD configuration, deployment, monitoring, and operational incident response.

You will collaborate closely with product managers and engineers across the company to deliver privacy‑preserving products used by millions of people worldwide.

Our codebase is primarily written in .NET and WinUI (C#/XAML), and we are building and integrating cross‑platform logical core libraries written in Rust.

Software quality is central to this role.

You will help define, maintain, and improve our testing stack, which includes unit tests, integration tests, and automated GUI tests (using FlaUI).