iOS Software Engineer (Payments)

Proton; Greater London; Hybrid; GBP 50,000 - 70,000; Full time

Job summary

A leading privacy-focused technology company in Greater London is seeking an iOS Engineer to develop and enhance features for its applications. You will work closely with cross-functional teams to define quality on Apple platforms. The ideal candidate has a strong background in Swift and experience driving change within their organization. This role also offers opportunities for mentorship and growth in a collaborative environment committed to user privacy.

Benefits

Flexible working hours

Comprehensive health insurance

Stock options

Learning and development opportunities

Daily lunch and snacks provided

Qualifications

• Experience in iOS with a focus on Swift.
• Passion for mentoring other engineers.
• Expertise in scalable software architecture.

Responsibilities

• Build and ship features for Proton's iOS apps.
• Maintain testing stack including unit and integration tests.
• Collaborate with product and engineering teams to define quality.

Skills

Swift

User experience design

API design

Concurrent programming

Mobile memory management

Job description

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. In some cases, Proton’s services have even been instrumental in saving lives by enabling secure and private communications in high-risk situations.

Proton is a profitable company that does not rely upon VC funding, supporting over 100 million user accounts with a growing team of over 500 people from over 50 different countries, coming from the world's top companies and universities. We value intelligence, learning potential and ambition in our hiring process. Adaptability is key as we navigate uncharted territories and redefine how business is conducted online.

Hiring at Proton is highly selective, with less than 1% of candidates hired. We believe smaller teams of exceptional talent will always prevail over larger teams with lower talent density. You'll have the opportunity to work with many of the world's top minds in their fields, ranging from former international math and science olympiad winners to chess champions.

We have a global mindset and big ambitions but remain a start-up at heart. We value empowerment and flexibility and keep our structure flat to keep moving fast and avoid unnecessary politics. Tired of blending into the crowd? Join us and do work you can truly be proud of. Check our open-source projects here !

The Payments Team

The goal of the Payments team is to enable revenue generation for the entire Proton ecosystem. This comes in the form of introducing new payment methods for users to architecting our client libraries. This team has impact across all of Proton's products and is critical to the success of the business as a whole.

• The Payments Team works to continuously expand the possibilities for users to pay with various payment methods, beyond just plain credit cards or Paypal - we aspire to create the best end to end payments experience for users globally
• The team works in tight collaboration with the Account Team (responsible for the Proton user lifecycle), the Proton Finance team, and every single Business Unit to ensure that plans, promotions and pricing meet user expectations -- we are the most cross-functional team in the business with direct impact on the ecosystem strategy

The Role

As an engineer on our iOS team you’ll build and ship features across Proton’s apps on iPhone, working closely with product and engineers across the company to define what “great” looks like on Apple platforms. Our codebase is primarily Swift with some Go, and we’re moving to a platform-independent Rust logical core that communicates with Swift via a generic interface, so Rust experience is a strong plus but not essential. Quality is central to the role: you’ll contribute to and maintain our testing stack, including unit tests for business logic, stubbed API tests for pseudo-integration, snapshot tests for UI and XCUITest for end-to-end user flows. You’ll join a team that pairs deep technical expertise with an obsession for simple, usable interfaces, shipping privacy-preserving products used by millions.

What we are looking for

• You have experience in iOS in particular with Swift
• You have a passion for mentoring other engineers and helping them grow
• You are passionate about user interaction, usability, and providing an excellent user experience
• Demonstrated experience driving change within an organisation and leading complex technical projects
• Extensive experience building maintainable and testable code bases, including API design and unit testing techniques
• Extensive experience with concurrent programming and mobile memory management
• A strong grasp of scalable software architecture and software engineering best practices
• An intuition for optimal user experience and design
• Rust experience not required, but a major plus
• Deep understanding of APNs, UNUserNotificationCenter and iOS background execution (silent pushes, background app refresh, background URLSession), and how these impact app reliability
• Experience building offline-first data flows with local persistence (Core Data, SQLite, Realm or similar) and conflict‑free sync

What We Offer

• Office First: 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 also enjoy working from home up to 30% of the time, while enjoying great company during our three core days in the office.
• 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.
• Food: Lunch and snacks are provided by Proton every day at our offices.
• Transport: We will always support our employees with transport costs through subsidizing public transport, bike allowances, or parking spaces based on your office location.
• Stock Options: At Proton, we are all owners of the company and you get stock options when you join us.
• Flexible Working: You can define your own working hours as long as it works with team meetings.
• Learning and Development: We are committed to your professional growth. Proton offers various learning opportunities, including training programs, conferences and events, and continual learning.
• Employee Benefits: Comprehensive health insurance plans, competitive retirement savings options, generous vacation and leave policies, and wellness programs.
• Work that Matters: Proton is a community‑first organization, 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. Read more about our impact here .

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.

If you need any extra support or reasonable adjustments during the hiring process, please let your talent partner know.

Candidate Privacy Notice

When you apply for a position, refer a candidate, or are considered for a role at Proton Technologies AG (Proton, we, us, or our), your information is stored in Greenhouse, in accordance with their Service Privacy Policy. This information is used to evaluate your suitability for the posted position. We also retain this information for consideration for future roles that you may apply for or that we believe may align with your background and skills.

If we no longer have a legitimate business need to process your information, we will either delete or anonymize it. Should you have any inquiries about how we use or manage your information, or if you wish to access, correct, or delete your data, please contact our privacy team at [e-mail].

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, even if the candidate is subsequently hired by Proton.

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