Senior Backend Engineer

Senior Backend Engineer – Platform Team

As a Senior Backend Engineer on the Platform team, you will design and build core, cross‑product systems used by Proton Mail and Proton Calendar, improve performance and cost‑efficiency of existing services, and apply data‑driven delivery practices to prioritize and ship features.

Responsibilities

• Architect and develop core systems that serve a large user base (100M+ users).
• Improve the performance of existing systems using monitoring, metrics, and cost‑analysis to identify time and infrastructure spend.
• Apply a data‑driven approach to technical decisions and delivery planning.
• Collaborate closely with backend and client‑side engineers, emphasizing quality and performance in everything shipped.
• Design and implement comprehensive testing strategies, including unit and integration tests, to ensure reliability of core systems.

Qualifications

• Strong experience in backend development with a proven record of designing, building, and scaling systems for large user bases.
• Demonstrated ability to improve the performance and cost‑efficiency of production systems.
• Hands‑on experience with monitoring and observability tooling such as Grafana, OpenTelemetry, or equivalent.
• Solid understanding of SQL (MySQL preferred) and data modeling.
• Experience leading technical initiatives end‑to‑end, from design through production.

Bonus Points

• Experience with client‑server sync or push‑notification systems.
• Experience with Kubernetes or other containerization technologies.
• Experience with PHP/Symfony, Rust, or Python.
• Full‑stack experience, comfortable working across the frontend as well as the backend.

What We Offer

• Work that matters: millions of users trust Proton with their privacy.
• Stock options: real ownership from day one.
• Technology: the right hardware and software to do your best work.
• Learning & Development: investment in your growth and real ownership from day one.
• Employee benefits: strong health coverage, retirement options, generous leave, and wellness support.
• In‑person collaboration: offices in Geneva, Zürich, Barcelona, London, and more.
• Food: lunch and snacks provided in office.
• Transport: coverage of public transport, bike allowances, or parking.
• Flexible working: schedule that works for you and the team.

Our Commitment to Diversity and Inclusion

At Proton, we believe diversity drives innovation and strengthens our mission to provide privacy as a default for all. We are committed to fostering an inclusive environment where all individuals, regardless of race, ethnicity, gender, age, sexual orientation, physical ability, or socio‑economic background, feel valued and empowered.

Candidate Privacy Notice

When you apply for this position, your information is stored in Greenhouse in accordance with their Service Privacy Policy. The information is used to evaluate your suitability for the posted position and may be retained for consideration of future roles. If you no longer have a legitimate business need to process your information, it will be deleted or anonymized. For inquiries, contact our privacy team at careers@proton.ch.

Compensation

Paris: 54,000 € – 83,000 € gross annually. Other locations: compensation will be discussed during the interview process. Final compensation will be determined based on the candidate's qualifications, skills, and prior experience.