Proton is hiring Senior Mobile Engineer (Inbox)

📍 Barcelona, Spain
🏢 On-site
🕔 Full-Time

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 new internet that serves the interests of all people. We need you, your voice, your ideas, and your ambition to make it happen.

We have enbarked on a journey to shape the next generation on Proton’s mobile clients. We are looking for exceptional individuals who believe in engineering as a problem-solving mindset and technology as a mean to and end: that of creating great custom experiences. We believe in distributed leadership within clear roles: for this position, it translates to end-to-end ownership of features or project, ability to drive effective change, innovation, pushing the boundaries of what is deemed to be possible. 

Job Description

As a Full-Stack Cross-Platform Mobile Engineer, you will play a pivotal role in re-architecting our mobile stack using Rust, Android/JetPackCompose and Swift UI. You will lead with an end-to-end ownership approach, ensuring timely delivery of high-quality, scalable solutions that will delight our customers. Your ambition and enthusiasm will drive innovation and excellence across our Mail and Calendar products.

Key Responsibilities

  • Develop and maintain cross-platform mobile applications for iOS and Android using a blend of cross-platform (Rust) and native technologies (Swift, Kotlin).
  • Take end-to-end ownership of mobile application development projects: you will be confortable with scoping projects, walking back from deadlines and able to discern the important from the superfluous. 
  • Foster a culture of innovation by exploring new technologies, methodologies, and approaches to mobile development. We tackle complex engineering challenges with creativity and ingenuity.
  • Optimize mobile applications for performance, usability, and responsiveness across different devices and screen sizes.
  • Master memory management, multithreading and concurrency mechanisms to enhance performance and responsiveness of mobile applications.
  • Design for scalability, considering factors such as data caching, network bandwidth, and server load.
  • Prioritize customer satisfaction by maintaining a customer-centric mindset throughout the development process, continuously seeking feedback and iterating to improve the user experience.

The ideal candidate will possess

  • Bachelor's degree in Computer Science, Engineering, or related field (or equivalent work experience).
  • Excellent problem-solving skills and ability to think outside the box to overcome challenges.
  • A passion for continuous learning and driving change in the rapidly evolving field of mobile development.
  • Excellent communication and interpersonal skills.
  • Proven experience developing mobile applications for iOS and Android using Swift, Kotlin as well as cross-platform technologies.
  • Proficiency with SwiftUI for iOS and Jetpack Compose for Android and familiarity  with Rust.
  • Strong understanding of mobile app architecture, design patterns, and best practices.
  • Knowledge of memory management techniques and best practices. 
  • Experience with multithreading and concurrency in mobile applications.
  • Good understanding of scalability considerations when it comes to engineering mobile applications.

Bonus points for previous experience working in a fast-paced, scale-up environment.


Why should you join Proton?

  • Be part of a movement - Proton is not just a product or service but a community-driven movement united by a shared vision of online freedom. Our services are open source, audited, and supported by community contributions. We give back to our community by maintaining core encryption libraries and by supporting other organizations furthering the same goals as us. Proton is free, open source, neutral, independent, and community first, while remaining financially sustainable.
  • Work with smart and dedicated people - Our team is diverse, collaborative, and tight-knit with people coming from all walks of life, including many of the world’s top academic institutions and organizations, such as MIT, Harvard, Stanford, Caltech, Cambridge, and ETH.
  • Join a strong brand - Our encrypted email service - Proton Mail - has grown to be a staple of online security and privacy. Proton has been featured in multiple popular television and film productions, such as Mr. Robot, Knives Out, Sounds of Metal, and more.
  • Grow with us - We’re one of Europe’s fastest-growing startups, doubling in size every year. Our growth gives you limitless career and educational opportunities as well as the opportunity to work side-by-side with many world-leading experts in their fields.
  • Have your voice heard - We value your opinion and encourage you to speak up and share your ideas and thoughts. At Proton, no problem is someone else’s problem. We collectively strive to do the right thing and be the undisputed best in the world at everything we do.
  • Benefits – these vary by location and type of contract but expect support on your vacation, parental leave, refreshment if working from the office, learning and development opportunities, equity for shared success, flexible working hours and remote work, company events and team building activities.

Proton does not accept unsolicited resumes from any sources other than directly from a candidate. Proton will not pay a fee for any placement resulting from the receipt of an unsolicited offer, even in a situation when the relevant candidate is employed by Proton.

To learn more about our privacy policy, please visit

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