Summary

The Software Engineer is responsible for developing and maintaining software systems that support Shift4’s products. This role focuses on implementing reliable, scalable, and maintainable solutions while collaborating closely with product managers, designers, and fellow engineers. The engineer contributes to multiple phases of the development lifecycle, including design, development, testing, and deployment, while continuously improving technical skills and contributing to engineering best practices.

Responsibilities

• Collaborate with product and engineering leaders to design, build, and enhance software solutions that deliver measurable customer and business impact.
• Develop and maintain internal applications through hands-on coding, testing, debugging, and deployment of maintainable and reusable software.
• Contribute to system design discussions and implement technical solutions aligned with established architectural standards.
• Work within an agile development process, participating in two-week sprints with the goal of delivering release-ready software each cycle.
• Integrate applications with backend services, APIs, and cloud-based infrastructure.
• Operate independently when required, exercising sound judgment in decision-making and ensuring proper documentation of technical designs and workflows.
• Write clean, well-documented, and testable code following team coding standards and best practices.
• Participate in code reviews to maintain quality and consistency across the codebase.
• Identify opportunities to improve application performance, reliability, and maintainability.
• Troubleshoot issues, debug software defects, and support resolution of production incidents when needed.
• Stay up to date with modern development practices, frameworks, and technologies.
• Ensure compliance with software governance, security, and quality policies.
• Perform additional tasks within the department as assigned by management.

Qualifications

• 3-5 years of professional software development experience.
• Proficiency in JavaScript/TypeScript, React Native, and related libraries (e.g., Redux, React Navigation).
• Experience integrating with backend systems (REST APIs or equivalent) and working with cloud services such as AWS or similar platforms.
• Experience with version control systems, particularly Git.
• Familiarity with CI/CD pipelines, automated testing, and release management practices.
• Understanding of mobile performance considerations and debugging techniques.
• Strong problem-solving skills and the ability to develop practical technical solutions.
• Motivation to take on increasing responsibility and ownership within an agile development team.

Preferred Qualifications:

• Understanding of modern web application development using TypeScript with frameworks such as React or Ember.
• Experience working with AWS-hosted backends and databases.
• Bachelor’s degree in Computer Science, Engineering, Information Systems, or a related field.
• Experience working with native iOS (Swift/Objective-C) or Android (Kotlin/Java) codebases.
• Familiarity with mobile security, data encryption, and compliance practices.
• Experience with a distributed software system.
• Relevant professional certifications are advantageous but not required.

Benefits:

The salary range for this position is starting at 4000 Eur Gross. The exact salary will be determined based on the candidate’s experience.

As an iOS Engineer at Flo, you'll help shape the mobile experience for millions of people, and do genuinely meaningful work in women's health. Our app is trusted by 1 in 4 women aged 18–44 in the US and used across 100+ countries, with machine learning and AI powering accurate cycle predictions and personalised, medically credible health insights.

We build large-scale mobile applications with rich, intuitive interfaces - optimised for speed, accessibility and privacy. You'll join a cross-functional team working across the full mobile lifecycle, from feature ideation through to release and iteration, with real ownership over value delivery end to end.

We're not a feature factory. Our engineers are pragmatic problem-solvers who thrive in fast-moving environments and care about what they ship. You'll have genuine scope to experiment, lead ambitious product initiatives and implement solutions that matter - not just clear a backlog. Flo is a constantly evolving product, and we give our engineers the trust and autonomy to evolve it.

Your Experience

• 6+ years in software engineering, with at least 3 years focused on building, shipping, and maintaining production mobile applications.
• Expert-level iOS development skills, with a proven track record of delivering high-quality apps at scale.
• Hands-on experience building complex mobile applications with rich, performant UIs — experience in global consumer-facing products is a strong plus.
• Deep proficiency in Swift; working knowledge of Objective-C and solid object-oriented design principles.
• Strong familiarity with Apple's ecosystem — frameworks, HIG guidelines, and end-to-end App Store submission and maintenance processes.
• Clear understanding of the mobile product lifecycle and comfortable working within Agile teams.
• A collaborative, growth-oriented mindset with the drive to take ownership and deliver.

Nice to have:

• Solid understanding of UX and interaction design principles, with the ability to collaborate effectively with designers and advocate for quality user experiences.
• Proven experience optimizing mobile app performance over constrained networks, including building and maintaining offline-first architectures.
• Hands-on experience with mobile CI/CD pipelines, including build automation, automated testing, and release workflows.
• Experience integrating with BI and analytics platforms, with familiarity in designing and interpreting A/B tests to drive product decisions.

What you'll be doing

You'll be responsible for:

• Building and maintaining features using modern frameworks, libraries, and internal component systems, ensuring consistency, scalability, and code quality across the codebase.
• Delivering polished, engaging user experiences that balance visual appeal with intuitive interaction design.
• Owning and contributing to a robust Continuous Delivery pipeline, ensuring fast, reliable, and safe releases to production.

#LI-Hybrid #LI-AJ1

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 

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