Senior Backend Engineer (Inbox)

Join Proton and build a better internet where privacy is the default

At Proton, we believe that privacy is a fundamental human right and the cornerstone of democracy. Since our inception in 2014, founded by a team of scientists from CERN, we have dedicated ourselves to providing free and open-source technology to millions worldwide, ensuring access to privacy, security and freedom online.

Our journey began with Proton Mail, the largest secure email service globally, and has since expanded to include Proton VPN, Proton Calendar, Proton Drive and Proton Pass. These tools empower individuals and organisations to take control of their personal data, break away from Big Tech's invasive practices and defeat censorship. Our work impacts hundreds of millions of lives, from activists on the front lines defending freedom to leaders in governments protecting sensitive information.

Role overview

Become part of the team that drives the development of Proton Mail and Proton Calendar. While your focus will be on the back-end architecture of these products, close collaboration with front-end teams is essential. You'll play a key role in designing and delivering robust, scalable systems that serve millions of users globally.

What you'll do

1. Take ownership of complex, cross-functional projects driving them from planning to execution, while ensuring team priorities are successfully met
2. Work closely with back-end and front-end (Web, Mobile, Desktop) engineers to build solutions while considering client limitations such as performance, bandwidth and device-specific constraints
3. Proactively identify and initiate new work streams and projects to drive forward team objectives
4. Demonstrate a product-oriented mindset, focusing on product engineering and design that meets the needs of the end-user
5. Collaborate with teams of client application developers to ensure that the back-end meets critical business and reliability requirements

What you'll bring

1. Strong experience in back-end development with a proven track record of working closely with client-side teams (Web, Mobile)
2. Experience in leading cross-functional projects, coordinating across multiple teams to deliver complex solutions
3. Strong product engineering mindset, with a focus on designing back-end systems that drive excellent user experience
4. Experience building scalable solutions, especially for systems that serve a wide variety of clients
5. Fluency in OOP and SOLID
6. Solid understanding of SQL (MySQL preferred) and data modelling
7. Good knowledge of unit and functional testing
8. Strong understanding of security best practices
9. Understanding of HTTP/REST, including both developing and consuming web-based APIs

Bonus points for

1. Operational experience, such as SRE or on-call, demonstrating ability to diagnose and troubleshoot complex problems for critical systems
2. Experience with Docker or similar containerisation technologies
3. Experience with CI/CD (Gitlab, Jenkins, etc.)
4. Experience with back-end web frameworks (Symfony, Spring, .NET)
5. Experience with modern PHP, Rust and Python
6. High-level understanding of cryptography concepts such as key exchange and the difference between symmetric and asymmetric encryption
7. Experience with DDD (Domain-Driven Design) and other enterprise patterns
8. Experience with metrics graphing/analysis toolkits such as Grafana and OpenTelemetry
9. Solid understanding of Redis or other caching technologies
10. Experience with OpenAPI specs or other API documentation frameworks

What we offer

1. 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
2. Learning & Development: we are committed to your professional growth - Proton offers various learning opportunities, including training programs, conferences/events and continual learning
3. Employee Benefits: comprehensive health insurance plans, competitive retirement savings options, generous vacation/leave policies and wellness programs
4. Stock Options: at Proton, we are all owners of the company and you get stock options when you join us
5. In-Person Collaboration: 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 enjoy working from home for up to 30% of the time, while enjoying great company culture during our three core days in the office (depending on the role, fully remote positions may also be available)
6. Food: lunch and snacks are provided by Proton every day at our offices
7. Transport: we'll always support our employees with transport costs through subsidising public transport, bike allowances or parking spaces based on your office location
8. Flexible Working: you can define your own working hours as long as it works with team meetings
9. Work that Matters: Proton is a community-first organisation, started with the support of a crowdfunding campaign and built with community input - to this day, Proton's only source of revenue is user subscriptions: over 100 million people trust and support Proton, and we put our users and community first in everything we do

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. We strive to create equal opportunities, promote open dialogue and support continuous learning to ensure every voice is heard and respected.