Senior Backend Engineer

Join Proton and build a better internet where privacy is the defaultProton was founded in 2014 by scientists from CERN on a simple truth:privacy is a fundamental human right. Since then, we’ve built the world’s largest encrypted email service (Proton Mail) and expanded into Proton VPN, Proton Drive, Proton Pass, and Proton Calendar—tools used by millions globally to protect their freedom, fight censorship, and keep their data safe. In some situations, Proton has literally helped save livesWe are profitable, independent (no VC control), and selectively hire from the top ~1% of applicants. Our 500+ team members across 50+ countries come from leading organizations and elite academic backgrounds. We move fast, keep hierarchy light, and prioritize impact over optics. If you want to do meaningful work with exceptionally high-caliber people, this is it.
Join us and do work you can truly be proud of.
Check ouropen-sourceprojectshereThe Foundation TeamThe Foundation team builds what the product teams build on: the shared backend framework, the internal libraries, the common services and abstractions that every Proton application reaches for. If several teams need it, it should exist once, and be good.
You will work in PHP for API related work, and in Rust for components where performance and memory safety justify it or for microservices. You will own libraries or initiatives end to end: design, implementation, documentation, versioning, and the migration path for everyone already depending on the old version.
Architecture is a large part of this role. Many engineers work in the same monorepo, which means module boundaries, dependency direction, and ownership are not academic concerns — they decide whether the codebase stays navigable or slowly turns into something nobody can change safely. You will help define those boundaries, make the structural calls that keep teams from stepping on each other, and do some work to enforce them: writing the RFC, adding rules, untangling the cycle that shouldn’t have been there. None of this happens in isolation. You will work closely with other teams who consume and use what you build.
What you will doDesign and build shared libraries, framework layers, and internal services used across every Proton productTurn recurring patterns into good abstractionsWrite documentation and examples people actually use, and treat adoption as part of shippingImprove the day-to-day: build times, local dev setup, test ergonomics, debuggability, developer experienceWork in the open with product teams — RFCs, design reviews, and the occasional pull request into someone else’s repo to show what you meanWork closely with other developers to help integrate libraries seamlessly into applicationsJob

requirements:
5+ years building and operating backend systems in production, including code you stayed responsible for long after launch, with a focus on modern PHPWorking knowledge of Rust, or clear evidence you can get there quickly — we care that you understand ownership and lifetimesGenuine taste in API design. You have opinions about naming, defaults, error handling, and what belongs in a library versus a serviceA feel for architecture at codebase scale — you have worked somewhere large enough that module boundaries and dependency direction mattered, and you have views on what keeps a monorepo healthyExperience evolving shared code that other teams depend on, and doing it without breaking themA security mindset. You think about how the abstraction you just wrote will be misusedThe influence to get an internal library adopted rather than worked around, and the patience to carry a design through disagreement between two teams who both think they’re rightBonus points for:Domain-Driven Design, or similar experience modelling complex domains where the boundaries matterBackground in developer tooling, platform, or DX teamsContributions to open source, especially libraries with real usersExperience migrating a codebase incrementally between architectures or languagesExperience with applied cryptography, key management, or end-to-end encrypted systemsExperience with building CI/CDWhat

We Offer
Work that Matters:millions of people trust Proton with their privacy. We answer only to our users — not advertisers, not investors with conflicting agendas, not governments. The work you do here is real, and the impact is measurable. (read more about our impact here)Work with smart and dedicated people -Our team is diverse, collaborative, and tight-knit with people coming from all walks of life, including many of the world’s top academic institutions and organizations, such as MIT, Harvard, Stanford, Caltech, Cambridge, and ETH.
Technology:you’ll get the right hardware and the right software you need to do your best work.
Learning & Development:we invest in your growth because sharp people make us better. Proton is one of the fastest ways to accelerate your career because you’ll be thrown into real challenges, with real ownership,