.(J-113) | Senior Back-end Engineer (Pass) Barcelona Barcelona, Catalonia, ES A better internet, where privacy is the default, is possible. Building this better internet might seem daunting or even unthinkable, but at Proton, this is what we do every day. Proton was founded in 2014 by a group of scientists who met at the European Organization for Nuclear Research (CERN). Our first product, Proton Mail, is now the world's largest encrypted email service. Subsequent Proton products, such as Proton VPN, Proton Calendar, and Proton Drive, give our users full control over how and with whom their data is shared. Today, Proton makes privacy universally accessible. Journalists from outlets like The Guardian and The New York Times, some of the world's largest organizations, and people in more than 180 countries have signed up for over 70 million accounts. Our diverse and dynamic team is made up of more than 400 members representing over 40 different nationalities. While we are based in Geneva, Switzerland, we have offices in Zurich, Prague, London, Vilnius, Skopje, Taipei, and many more employees working remotely around the world. Join one of Europe's fastest-growing companies to help us solve challenging problems and build new products that will reach hundreds of millions of people. We want to create more than just one of the world's most impactful tech companies; we want to create a newinternet that serves the interests of all people. We need you, your voice, your ideas, and your ambition to make it happen.Purpose of the role: Join the team responsible for Proton Pass and SimpleLogin. This role focuses on the backend side of those products, but the team can give a helping hand to the frontend teams.What you will do:Code in our shared backend frameworkWork closely with a group of Back-End Engineers and Architects to build resilient, massively-scalable solutions for millions of people to rely onCollaborate with teams of client application developers to ensure that the back-end meets critical business and reliability requirementsDocument back-end capabilities and their proper use so that all Proton clients can implement correctly-functioning solutionsImprove vital systems such as the systems responsible for cleaning up file revisions and returning quota to usersJob requirements:Strong experience with backend developmentExperience building scalable solutionsFluent with OOP and SOLIDFluent with at least one strongly typed languageSolid understanding of SQL (MySQL preferred) and data modellingKnowledgeable about unit and functional testingSolid understanding of security best practicesSolid understanding of HTTP / REST, including both developing and consuming web-based APIsBonus points for:Operational experience such as SRE or on-call, demonstrating ability to diagnose and troubleshoot complex problems for critical systemsExperience with Docker or similar containerization technologiesExperience with CI / CD (Gitlab, Jenkins, etc