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 organizations 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, 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 will 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 team:

Proton VPN enables millions of people to connect securely and privately, even in places where the internet is restricted or unreliable. Delivering that experience means our service must perform flawlessly under highly variable, real-world conditions.

We are looking for a Senior Performance Engineer to lead our efforts in making Proton VPN the fastest, most resilient, and most reliable VPN service in the world.

You will define and drive the measurement, analysis, and optimization of Proton VPN’s end-to-end performance, across clients, platforms, and global infrastructure. You’ll help ensure that every connection is fast, stable, and private, regardless of where the user is or what network they’re on.

What you will do: 

• Design and own Proton VPN’s performance framework, defining metrics and KPIs that reflect the real-world experience of users (time-to-connect, throughput, latency, stability, reconnection rates, etc.).
• Develop distributed testing systems that simulate real network conditions, including low bandwidth, packet loss, and high-latency scenarios.
• Continuously measure and analyze performance across platforms (desktop, mobile, backend) and regions to identify bottlenecks and regressions.
• Collaborate with backend, R&D, and client teams to optimize protocol handling, connection setup, routing, and encryption performance.
• Create dashboards, reports, and automated alerts to track global performance health.
• Contribute to the design of resilient connectivity strategies that adapt dynamically to variable network conditions.
• Serve as the performance champion within the engineering organization, mentoring others and driving a data-driven performance culture.

Job requirements: 

Technical Skills

• 5+ years of experience in performance engineering or systems QA, ideally in networking, VPNs, or distributed systems.
• Knowledge of network protocols (TCP/IP, UDP, TLS, WireGuard, debugging, manipulating, and performance profiling tools.
• Proven ability to analyze latency, throughput, and stability metrics across multiple layers (client, OS, transport, application).
• Proficiency in Python (or similar scripting language)
• Familiarity with network emulation and simulation tools (e.g., tc/netem, iperf, IPTables/nfTables…).
• Experience with monitoring and observability stacks (Grafana, Prometheus, Loki) and CI/CD pipelines.
• Cross-platform experience with Linux, macOS, Windows, Android, and iOS preferred.

Bonus points for: 

• Experience with Rust/C/C++/System development

Soft Skills

• Analytical and methodical, yet creative in solving complex performance problems.
• Comfortable working with uncertainty and non-deterministic conditions.
• Collaborative mindset, able to work across client, infrastructure, and data teams.
• Strong communication and documentation skills in English.

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 careers@proton.ch.

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.

To learn more about our privacy policy, please visit our privacy policy page.

#LI-Onsite

About Proton

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

Proton was founded in 2014 by scientists from CERN on a simple truth: privacy is a fundamental human right. Since then, we’ve built the world’s largest encrypted email service (Proton Mail) and expanded into Proton VPN, Proton Drive, Proton Pass, and Proton Calendar—tools used by millions globally to protect their freedom, fight censorship, and keep their data safe. In some situations, Proton has literally helped save lives!

We are profitable, independent (no VC control), and selectively hire from the top ~1% of applicants. Our 500+ team members across 50+ countries come from leading organizations and elite academic backgrounds. We move fast, keep hierarchy light, and prioritize impact over optics. If you want to do meaningful work with exceptionally high-caliber people, this is it. Join us and do work you can truly be proud of. Check our open-source projects here!

The team:

Join a world-class Linux engineering team at the forefront of privacy-focused open-source development, where your contributions directly impact millions of users worldwide. Our engineers are passionate problem-solvers who thrive in a fast-paced, collaborative environment, tackling complex technical challenges with creativity and rigor. We value autonomy, technical excellence, and a shared commitment to building software that genuinely makes the world a safer place. If you are driven by purpose and love working alongside exceptionally talented people, you will feel right at home here.

What you will do:

• Design, develop, and maintain robust automated test frameworks and pipelines for Linux-based open-source software

• Write and execute functional, integration, regression, and end-to-end test suites to ensure product reliability and security

• Collaborate closely with developers to define testability requirements and integrate automated tests into CI/CD workflows

• Identify, document, and track software defects, working with engineering teams to drive timely resolution

• Perform exploratory and risk-based testing with a strong focus on privacy, data integrity, and security compliance

• Develop and maintain test infrastructure, including virtual machines, containers, and Linux environment configurations

• Analyze test results, generate reports, and provide actionable insights to improve software quality and release confidence

• Contribute to the continuous improvement of QA processes, tools, and best practices across the engineering organization

• Participate in code reviews for test code, ensuring maintainability, scalability, and adherence to engineering standards

• Stay current with the latest Linux ecosystem developments, testing methodologies, and open-source tooling

What we are looking for:

• 3–5 years of hands-on experience in software test automation, with a strong focus on Linux-based environments

• Solid proficiency in at least one scripting or programming language commonly used for test automation, such as Python, Bash, or Go

• Proven experience designing and maintaining automated test frameworks (e.g., pytest, Robot Framework, or similar)

• Good understanding of CI/CD pipelines and experience integrating automated tests with tools such as GitLab CI, Jenkins, or GitHub Actions

• Familiarity with containerization and virtualization technologies, including Docker, QEMU, or similar tools for test environment management

• Solid knowledge of Linux internals, system administration, and command-line tooling

• Experience with version control systems, particularly Git, and comfort working in an open-source collaborative development model

• Understanding of software security principles and privacy-by-design concepts is a strong plus

• Ability to read and understand application source code to improve test coverage and identify edge cases

• Strong analytical and problem-solving skills, with a structured and detail-oriented approach to quality assurance

• Good communication skills and ability to work effectively in a remote, internationally distributed team

• A genuine passion for open-source software, privacy, and building technology that has a positive impact on society

What We Offer:

• Work that Matters: millions of people trust Proton with their privacy. We answer only to our users — not advertisers, not investors with conflicting agendas, not governments. The work you do here is real, and the impact is measurable. (read more about our impact here)

• Stock Options: at Proton, we all have the opportunity to be owners of the company. From day one, you have a real stake in what we're building. When Proton wins, you win.

• Technology: you'll get the right hardware and the right software you need to do your best work.

• Learning & Development: we invest in your growth because sharp people make us better. Proton is one of the fastest ways to accelerate your career because you'll be thrown into real challenges, with real ownership, from day one.

• Employee Benefits: your wellbeing isn't an afterthought. We offer strong health coverage, solid retirement options, generous leave, and wellness support so you can bring your best self to work every day

• In-Person Collaboration: Amazing things happen when passionate, smart, and purposeful people get together in the same room. With offices across Geneva, Zürich, Barcelona, London and more, you'll spend most of your time collaborating face-to-face with people who genuinely care about what they're building

• Food: Lunch and snacks are on us every day in our offices so you can focus on the work and not on what's for lunch.

• Transport: getting to the office shouldn't cost you. We cover public transport, bike allowances, or parking, whichever works for you.

• Flexible Working: you own your schedule. Set hours that work for you and your team — because outcomes matter more than when the clock says you started.

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 careers@proton.ch.

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.

To learn more about our privacy policy, please visit our privacy policy page.

Salary range (Vilnius) - 46.100 - 60.000 EUR gross annual 

#LI-Onsite

About Proton

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

Proton was founded in 2014 by scientists from CERN on a simple truth: privacy is a fundamental human right. Since then, we’ve built the world’s largest encrypted email service (Proton Mail) and expanded into Proton VPN, Proton Drive, Proton Pass, and Proton Calendar—tools used by millions globally to protect their freedom, fight censorship, and keep their data safe. In some situations, Proton has literally helped save lives!

We are profitable, independent (no VC control), and selectively hire from the top ~1% of applicants. Our 500+ team members across 50+ countries come from leading organizations and elite academic backgrounds. We move fast, keep hierarchy light, and prioritize impact over optics. If you want to do meaningful work with exceptionally high-caliber people, this is it. Join us and do work you can truly be proud of. Check our open-source projects here!

The team:

We're a tight-knit, passionate Android engineering team building privacy-first apps that are trusted by millions of people around the world — and yes, our code is open source, so your work is truly out there making a difference. We move fast, skip the bureaucracy, and genuinely care about what we ship. Whether you're deep in Espresso tests or debating architecture over lunch, you'll be surrounded by people who are as excited about quality as you are. If you love Android, hate flaky tests, and want your work to actually matter — you'll fit right in.

Tech Stack and Tools:

Kotlin, Java, Espresso, UI Automator, Maestro

What you will do:

• Design, develop, and maintain automated test frameworks and pipelines for Proton's Android applications

• Write and execute UI, functional, integration, and end-to-end test suites using modern Android testing tools and best practices

• Work hand-in-hand with Android developers to define testability requirements and embed automated tests into CI/CD workflows

• Hunt down bugs, document them clearly, and collaborate with the team to get them fixed fast

• Perform exploratory and risk-based testing with a sharp eye on privacy, data integrity, and security behavior

• Own and evolve the Android test infrastructure, including emulator farms, device labs, and test environment configurations

• Dig into test results, spot patterns, and turn findings into actionable improvements that raise the quality bar

• Champion QA best practices across the team and help shape how we think about quality at every stage of development

• Review test code with the same rigor as production code — maintainability and scalability matter here

• Keep up with the Android ecosystem, new testing frameworks, and open-source tooling so we're always ahead of the curve

What we are looking for:

• 3–5 years of hands-on experience in Android test automation, ideally on consumer-facing apps with a large user base

• Strong proficiency in Kotlin and/or Java, with solid experience writing clean, maintainable test code

• Proven experience with Android testing frameworks such as Espresso, UI Automator, or Maestro

• Good understanding of CI/CD pipelines and experience integrating Android tests with tools like GitLab CI, GitHub Actions, or similar

• Familiarity with Android emulators, physical device testing, and cloud-based device farms (e.g., Firebase Test Lab)

• Comfortable navigating Android Studio, ADB, and the broader Android development toolchain

• Experience with version control using Git, and a natural fit in an open-source collaborative workflow

• A good nose for security and privacy issues — understanding of privacy-by-design is a real plus

• Ability to read and understand application source code to sharpen test coverage and catch edge cases early

• Sharp analytical mindset with a structured, detail-oriented approach — you don't let things slip through the cracks

• Great communicator who thrives in a remote-friendly, internationally distributed team

• Genuine enthusiasm for open-source software, Android, and building technology that protects people's privacy

What We Offer:

• Work that Matters: millions of people trust Proton with their privacy. We answer only to our users — not advertisers, not investors with conflicting agendas, not governments. The work you do here is real, and the impact is measurable. (read more about our impact here)

• Stock Options: at Proton, we all have the opportunity to be owners of the company. From day one, you have a real stake in what we're building. When Proton wins, you win.

• Technology: you'll get the right hardware and the right software you need to do your best work.

• Learning & Development: we invest in your growth because sharp people make us better. Proton is one of the fastest ways to accelerate your career because you'll be thrown into real challenges, with real ownership, from day one.

• Employee Benefits: your wellbeing isn't an afterthought. We offer strong health coverage, solid retirement options, generous leave, and wellness support so you can bring your best self to work every day

• In-Person Collaboration: Amazing things happen when passionate, smart, and purposeful people get together in the same room. With offices across Geneva, Zürich, Barcelona, London and more, you'll spend most of your time collaborating face-to-face with people who genuinely care about what they're building

• Food: Lunch and snacks are on us every day in our offices so you can focus on the work and not on what's for lunch.

• Transport: getting to the office shouldn't cost you. We cover public transport, bike allowances, or parking, whichever works for you.

• Flexible Working: you own your schedule. Set hours that work for you and your team — because outcomes matter more than when the clock says you started.

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 careers@proton.ch.

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.

To learn more about our privacy policy, please visit our privacy policy page.

Salary range (Vilnius) - 48.800 - 54.200 EUR gross annual 

#LI-Onsite

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 organizations 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, 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 will 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!

Purpose of the role:  

Proton continues to grow rapidly as increasing numbers of people across the globe seek greater privacy controls of their information online. To accelerate our growth, we are seeking a senior leader to drive engineering for one of our many existing or upcoming Products.

We are seeking a Director of Engineering to one of our existing or upcoming Products. This role involves setting and executing technical strategy, team management, and working closely with your senior product managers counterparts, to ensure high-velocity delivery of new products.

As a key member of the engineering leadership team, you will shape the company’s technical strategy and contribute to Proton’s mission of creating a privacy-centric internet. Each product will have its unique challenges and areas of focus, nevertheless we require all Engineering Directors for our Products to have a demonstrated track record of building and scaling customer facing applications, in either a B2C or B2B context, for millions of users, across multiple platforms (mobile, desktop, backend systems and platforms).

In addition to technical expertise, Engineering Directors as senior leaders within Proton, have excellent communication skills, a business mindset, and a strong sense of empathy for the end customers.

What you will do:

• Setting technical direction and vision for one of our Products
• Lead technical design and platform discussions
• Drive continuous improvement in our DevSecOps practices, and improve lead times and time to market while maintaining exceptional standards of product quality
• Hold yourself and team accountable for timely delivery of scalable, quality-focus user experiences and features
• Develop efficient processes, and motivate your team to operate with high velocity, ownership, and accountability
• Lead through others, and develop the next generation of engineering leaders at Proton
• Inspire, coach, and develop your teams
• Optimize your organizational structure, and continuously raise the bar on hiring
• Build strong relationships with senior leaders, and advance your long-term platform and engineering vision
• Contribute to Proton's technology and open source communities
• Foster an inclusive and diverse environment for your team to show up and give their best each day

Our Tech stack:

• Applied cryptography (PGP, TLS, etc.)
• REST APIs
• Event architectures 
• HTTP networking
• SQL, Redis
• PHP (Symfony), Rust, Python
• iOS, macOS (Swift)
• Android (Kotlin, Jetpack)
• Web (Typescript, React)
• Desktop (C#, Swift)
• Infrastructure: MySQL / Ceph

We need you to have:

• Experience in software engineering in progressively complex roles
• Experience directly leading and managing engineers
• Demonstrable experience as a manager of managers
• A history of collaboration with senior leaders in engineering, product on developing technical and product strategy
• Great empathy and collaboration skills, and even greater resilience
• A curious, passionate, and growth-oriented mindset
• Deep experience as a hands-on software engineer creating well-crafted, maintainable systems
• Mobile-first background (ideally former mobile developer)
• Practical experience leading DevOps and SRE initiatives and driving best practices
• Experience with cryptography preferred
• Bonus points for each of the following:

• • Experience with performance tuning and scaling across client, backend, infrastructure
  • Working closely with C-level executives to align on direction, vision and execution
  • Having both, the experience of operating at global scale with millions of customers but also thriving in the chaotic growth phase of scaling up to reach it.

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 careers@proton.ch.

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.

To learn more about our privacy policy, please visit our privacy policy page.

#LI-ONSITE

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 organizations 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, 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 will 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 Drive Team:

Proton Drive is our end-to-end encrypted cloud storage service that makes privacy simple and accessible. Built on the same security principles that power Proton Mail, Proton Drive ensures that files, photos, and documents remain fully encrypted—both in transit and at rest—so only you can access them. Available on web, desktop, and mobile, it enables users to securely store, share, and collaborate without sacrificing privacy or control. By offering a truly private alternative to Big Tech’s data-driven ecosystems, Proton Drive plays a key role in building an internet where privacy is the default.

The Role:

Proton is a mobile-first company building an Internet that respects privacy and puts people, not advertisers, first. As an engineer on our Apple team you’ll build and ship features across Proton’s apps on iPhone, iPad and macOS, 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. 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.

We we are looking for:

• You have experience in iOS or macOS development, in particular with Swift (7+ years)
• 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 organization and leading complex technical projects
• Extensive experience building maintainable and testable code bases, including API design and unit testing techniques
• Extensive experience with multithreading 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

Even if you don’t meet all the requirements listed above, but feel you could still be a great fit, please still apply.

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 careers@proton.ch.

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.

To learn more about our privacy policy, please visit our privacy policy page.

#LI-ONSITE

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 organizations 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, 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 will 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 team:

You strive for perfection and are obsessed with details? You are the one that catches the needle in the haystack in no time? You have a strong background in Quality Assurance and good technical skills? You like to work in a young and dynamic environment? Our QA team is looking for you.
This team is part of our VPN department. The team members are spread in different office locations across Europe. They are responsible for raising the quality standards of our native clients on all platforms as well as maintaining, improving and executing test plans. They are working in strict contact with our automation engineers to get repetitive tasks implemented in our automated test suites while focusing on the improvements of the testing process. Also, they work hand-in-hand with the development and product teams and will provide quality feedback on every stage of the software development lifecycle.

Tech Stack and Tools:

Apple, XCode, XCTest

What you will do:

As our iOS Test Automation Engineer, you’ll be the guardian of app quality. You will:

• Design, build, and maintain automated test frameworks and test suites for iOS.

• Collaborate closely with product managers, designers, and developers to ensure features are testable and reliable.

• Integrate test automation into CI/CD pipelines to deliver fast, smooth, and fearless releases.

• Debug, analyze, and triage test failures — helping the team get to the root cause quickly.

• Continuously explore new tools, frameworks, and practices to improve test coverage, speed, and scalability.

What we are looking for:

• 5+ years of test automation experience, with a focus on iOS apps.

• Strong coding skills in Swift (bonus if you know Objective-C too).

• Experience with iOS testing frameworks XCTest/XCUITest.

• Familiarity with CI/CD pipelines (Gitlab, Harbor, Docker).

• A quality-first mindset and a passion for clean, maintainable code.

• Team-player energy — you love collaborating to build products users love.

Bonus points for:

• Experience with device clouds (Firebase Test Lab, BrowserStack, Saucelabs).

• Knowledge of API testing (REST, GraphQL) to validate end-to-end scenarios.

• Experience with performance, load, or accessibility testing for mobile apps.

• Contributions to open-source testing tools or your own side projects.

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 careers@proton.ch.

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.

To learn more about our privacy policy, please visit our privacy policy page.

Salary range (Vilnius) - 55.000 - 71.000 EUR gross annual 

#LI-Onsite

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 organizations 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 today supports over 100 million user accounts with a growing team of over 500 people from over 50 different countries, 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. We believe smaller teams of exceptional talent will always prevail over larger teams with lower talent density. Proton has become profitable and reached scale without relying upon VC funding, largely due to superior talent that allows us to do things faster, more creatively, and more efficiently.

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 social media pages to learn more about us: Twitter, Reddit, Instagram.

The role:

You will be responsible for designing, building, maintaining and evolving Proton applications on Windows. This includes not only building the application internals (managing and syncing local and remote state, performing cryptographic operations, etc) but also helping us to build a resilient, scalable application (graceful degradation; log and metrics streams free of personally identifiable information). You will be involved in the entire application lifecycle, including Gitlab configuration, deployments, monitoring and alerting, and operational incident response. While this position is not a "full-stack" position, you will be expected to collaborate with backend engineers to drive any necessary changes and/or new features needed for the Windows experience.

What you will do:

• Be part of a small team working to bring a "privacy by default" solution to our clients on Windows.
• Develop an application that delights a wide range of users, from layperson to technical, and gives confidence that their online privacy is in good hands - while getting the complexity of end-to-end encryption out of the way.
• Invest in testing and automation to improve the team's productivity and software delivery cadence.
• Think critically on how to divide problems into iterations of simpler, composable solutions. Re-evaluate the minimum scope as necessary to meet objectives on-time.
• Insist on high standards for application monitoring and alerting, in order to ensure a smooth customer experience at all times.

We we are looking for:

• Strong experience in .NET development
• Strong experience building and maintaining Desktop Windows applications
• Strong experience with concurrent multi-threaded programming
• Working knowledge of file systems
• Working knowledge of Git
• Bachelor's or master’s degree in a relevant field of study
• Experience with owning and maintaining large software components
• Experience with gradual rollouts and metrics/monitoring/alerting frameworks

Even if you don’t meet all the requirements listed above, but feel you could still be a great fit, please still apply.

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 careers@proton.ch.

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.

To learn more about our privacy policy, please visit our privacy policy page.

#LI-ONSITE

The Scale of the Challenge

At Flo we don’t just have users, we have a global community. We are the #1 women’s health app, in the last month alone, we saw 8.6M new installs and a 2.8M increase in active users.

This level of growth requires world-class engineering — increasingly augmented by AI, with engineers moving towards agentic development, where they design systems that collaborate with AI agents rather than writing everything manually. We are looking for a Senior DevEx Engineer to join Velocity, our Internal Platform team. Your mission is to build the foundation that allows our engineering organization to ship code faster, safer, and at a scale most engineers never get to encounter.

The Mission: Velocity

The Velocity team exists to eliminate friction. We treat our internal developers as our customers. You will:

• Abstract Complexity: Build intuitive tooling that enables self-service allowing devs to focus on product logic.
• Standardize Excellence: Bake best-practices, security, observability, and scalability into the core stack so they aren't afterthoughts.

What You Will Do

• Developer Experience: Build self-service tools that give product teams autonomy without sacrificing system stability.
• Platform Engineering: Architect and evolve our core stack (AWS, EKS, Terraform).
• Systems Resilience: Lead reliability initiatives, including business continuity planning and a sustainable on-call rotation.
• High-Scale Privacy: Support the infrastructure for industry-leading privacy features, such as our TIME-recognized "Anonymous Mode."
• Observability: Implement best-in-class monitoring (metrics, logs, tracing) to ensure issues are identified and mitigated before they impact the user.

What You Bring

• Experience: 6+ years in Infrastructure, DevEx, SRE, or DevOps roles supporting high-traffic, distributed environments.
• Cloud Native Mastery: Deep expertise in AWS and Kubernetes (K8s) is essential.
• Automation Mindset: Proficient in Infrastructure as Code (Terraform) and Configuration Management.
• Technical Breadth: Ability to script and build tools in multiple languages (Python, Go, Scala, or Bash).
• Deep Systems Knowledge: You’re comfortable debugging at the Linux kernel level and analyzing performance via, for example,  flame graphs.
• Communication: A "doc-first" mentality and the ability to collaborate across distributed product teams.

Bonus Points

• Background in hardening infrastructure for high-compliance or security-sensitive environments.
• Experience scaling consumer tech platforms with millions of concurrent users.
• Professional Accreditation such as AWS Professional Architect, CKAD or KCSA.

Why Join Flo?

• High Impact: Flo is re-writing women’s health. 
• Autonomy: We hire experts and empower you to deliver.
• Cutting-Edge Stack: Work with modern tools like Sentry, EKS, and Terraform in a fast-paced, "fail-forward" environment at a huge scale.

The Scale of the Challenge

At Flo we don't just have users, we have a global community. We are the #1 women's health app, in the last month alone, we saw 8.6M new installs and a 2.8M increase in active users.

When millions of people trust you with their most personal health data, security isn't a feature — it's a foundation. We are looking for a Cloud Security Engineer to join Velocity, our Internal Platform team. Your mission is to ensure that every system, pipeline, and tool our engineers rely on is secure by default — so they can ship fast without ever compromising trust.

The Mission: Velocity

The Velocity team exists to eliminate friction. We build and own the foundation everything else runs on: cloud infrastructure, developer tooling, and SRE practices. You will:

• Embed Security Into the Platform: Bake security, compliance, and best practices into the core stack so they're invisible to developers and impossible to skip.
• Automate Everything: Drive security-as-code across infrastructure, CI/CD pipelines, and container lifecycles — making manual gates a thing of the past.

What You Will Do

• Cloud Security Posture: Own and continuously strengthen Flo's AWS security posture using tools like GuardDuty, Inspector, Security Hub, and SSM Patch Manager.
• Container & Supply Chain Security: Harden container image security end-to-end — patch vulnerabilities automatically with Copacetic, sign and verify images with Cosign/Sigstore, and enforce policies at admission with Kyverno.
• Policy as Code: Manage CI/CD security across the organisation using policy-as-code tooling (Kyverno, Checkov), ensuring standards are enforced programmatically.
• Security Observability: Build visibility into security performance by measuring and visualising actionable metrics using tools like Databricks Dashboards or Looker.
• High-Scale Privacy: Support the infrastructure for industry-leading privacy features, such as our TIME-recognised "Anonymous Mode."
• Culture & Thought Leadership: Shape Flo's broader security culture through proactive engagement, documentation, and cross-team collaboration.

What You Bring

• Experience: 7+ years in Infrastructure Security, Cloud Security, or Security Engineering roles.
• Cloud Native Mastery: Deep expertise in AWS security services and best practices is essential.
• Infrastructure as Code: Proficient in Terraform and Terragrunt — you run everything as code.
• Container Security: Strong knowledge of Kubernetes security, image hardening, and admission control.
• Identity & Access: Solid understanding of identity management principles — SSO, OAuth, JWT, SAML.
• Automation Mindset: Comfortable scripting in Python, Bash, or similar to automate security workflows.
• Network Security: Understanding of modern network security principles and their practical application.
• SSDLC: Experience building Secure Software Development Lifecycle phases into engineering workflows.

Bonus Points

• Experience with security monitoring and event correlation systems (IDS/IPS, SIEM, AWS-native tooling).
• Knowledge of Zero Trust Architecture and its implementations (e.g., Cloudflare).
• Familiarity with secret management processes and tools.
• Experience in multi-cloud environments (AWS and preferably GCP).
• Understanding of business continuity principles (BIA, DRP).
• Professional accreditations such as AWS Security Specialty, CKS, or CISSP.

Why Join Flo?

• High Impact: Your work directly protects the health data of millions - Flo is rewriting women's health, and you'll make sure it's done securely.
• Autonomy: We hire experts and empower you to deliver.
• Cutting-Edge Stack: Work with modern security tooling (GuardDuty, Kyverno, Cosign, Elastic Cloud Security) deployed on real production infrastructure at massive scale.