Senior Backend Engineer (Platform)

TL;DR

Senior Backend Engineer (Platform): Building and optimizing core, cross-product systems for Proton Mail and Calendar with an accent on scalability, cost-efficiency, and performance. Focus on designing shared foundations, implementing observability, and driving data-driven technical initiatives to support a user base of over 100 million.

Location: Must be based in or able to work from Paris or Geneva

Salary: €54,000–€83,000 (Paris)

Company

Proton is a privacy-focused technology company founded by CERN scientists, providing encrypted email, VPN, and productivity tools to millions globally.

What you will do

• Architect and develop core, cross-product systems shared by Proton Mail and Calendar.
• Improve system performance and infrastructure cost-efficiency using monitoring and metrics.
• Drive data-driven technical decisions and delivery planning for the platform team.
• Collaborate with backend and client engineers to ensure high quality and performance.
• Develop comprehensive testing strategies, including unit and integration tests.

Requirements

• Strong experience in backend development with systems serving 100M+ users.
• Proven ability to optimize performance and cost-efficiency in production systems.
• Hands-on experience with monitoring and observability tools like Grafana or OpenTelemetry.
• Solid understanding of SQL (MySQL preferred) and data modeling.
• Experience leading technical initiatives end-to-end from design to production.

Nice to have

• Experience with client-server sync or push-notification systems.
• Familiarity with Kubernetes or containerization technologies.
• Proficiency in PHP/Symfony, Rust, or Python.
• Full-stack experience.

Culture & Benefits

• Ownership through stock options from day one.
• Strong health coverage, retirement options, and generous leave.
• Daily catered lunch and snacks in the office.
• Support for public transport, bike allowances, or parking.
• Flexible working hours focused on outcomes.