Senior Backend Engineer - Platform; Inbox

Paris;

Geneva

Our business unit, Inbox, is a cross-functional team of engineers, product managers, designers, and data analysts driving Proton Mail and Proton Calendar. Our mission is to create an end-to-end encrypted solution with a better user experience than competing products. The Platform team builds the shared foundations and systems used by Mail and Calendar to scale reliably and cost-effectively. Over the next year, the team focuses on efficiency and cost reduction.

The Platform team partners with the product team on new systems such as how client apps receive updates from the server (e.g., new email and calendar event delivery) while improving performance of existing production systems. Quality and performance are treated as first-class concerns in everything we ship.

As a Senior Backend Engineer on the Platform team, you’ll contribute hands-on experience with data-driven delivery, monitoring, and planning. You’ll work with the product team to design new systems and with the rest of the team to improve the performance of existing systems.

• Architect and develop core systems: Design and build core, cross-product systems shared by Proton Mail and Calendar, with scale and cost-efficiency as primary constraints.
• Performance: Improve the performance of existing systems using monitoring and metrics to identify where time and infrastructure spend go, and drive cost-reduction initiatives across shared platform components.
• Data-driven delivery: Apply data-driven decisions to technical choices and delivery planning, shaping how the team measures and prioritizes work.
• Collaboration: Work closely with backend and client engineers, with a strong emphasis on quality and performance in every release.
• Testing: Develop and implement comprehensive testing strategies, including unit and integration tests, to ensure reliability of core systems.

• Strong experience in backend development, with a track record of designing, building and scaling systems serving a large user base (100M+).
• Demonstrated ability to improve performance and cost-efficiency of systems in production.
• Hands-on experience with monitoring and observability tooling (e.g., Grafana, Open Telemetry, or equivalent) and a data-driven approach.
• Solid understanding of SQL (MySQL preferred) and data modeling.
• Experience leading a technical initiative end-to-end, from design through production.
• 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 frontend and backend.

What We Offer

We offer ways to work on meaningful projects with a focus on privacy and user trust, opportunities for growth, and a collaborative, globally distributed team.

We value diversity and strive to create an inclusive environment where all individuals feel respected and able to contribute. If you need any extra support or reasonable adjustments during the hiring process, please let your talent partner know.

When you apply for a position, your information is stored in our systems in accordance with our privacy practices. We will delete or anonymize data when there is no legitimate business need to process it. For inquiries about how we use or manage your information, contact our privacy team at careers.

Proton does not accept unsolicited resumes from any sources other than directly from candidates. We will not pay a fee for any placement resulting from an unsolicited offer.