Ilir Sela started Slice with the belief that local pizzerias deserve all of the advantages of major franchises without compromising their independence. Starting with his family’s pizzerias, we now empower over tens of thousands of restaurants with the technology, services, and collective power that owners need to better serve their digitally minded customers and build lasting businesses. We’re growing and adding more talent to help fulfil this valuable mission. That’s where you come in.

This position is open to applicants across all of the UK on a remote basis, with the physical office located in Belfast, Northern Ireland.

The Role

By applying your Mobile experience, and software development skills, you will build high quality and intuitive experiences for customer-facing and business-facing apps. You will collaborate with other developers to build scalable solutions that make it easy to build high quality products, and you will work alongside designers and other stakeholders to build exciting new features and refine existing experiences. You will integrate with our custom built in-shop embedded projects. Knowledge of more than one mobile stack as well as an interest in embedded systems is a bonus. 

For this role, we are focusing on hiring at the Senior level, which requires broad professional mobile development experience and a strong track record of leading complex initiatives and delivering broad impact. We recognise that job titles and responsibilities vary across companies; throughout our interview process we assess each candidate’s experience, technical depth and overall impact to ensure alignment with the appropriate level at Slice.

The Team

You will be part of our Devices development team that is responsible for all of our customer-facing and business-facing mobile and embedded products. Think pizza ordering apps, Point-of-sale and Kiosk’s to name a few. We believe that consolidating our skills on platform-specific teams leads to a better development environment where you can collaborate, learn from and grow alongside other device experts. Our team brings together talented developers from across the US, UK, and Eastern Europe, each contributing unique perspectives and expertise to drive success.

The Winning Recipe

We’re looking for creative, entrepreneurial developers who are excited to build world-class products for small businesses and their customers. 

The core competencies this role calls for:

• Proven experience developing iOS apps with Swift, SwiftUI, Combine and Core Data.
• Hands-on experience designing, developing and maintaining Android applications with Kotlin & Jetpack Compose is required.
• Technical leadership and strategic impact: able to guide complex projects end-to-end, influence architecture decisions and lead peers.
• Experience with Python, particularly in developing web services, is a plus.
• Embedded systems experience is highly desirable.
• Able to clearly express opinions on product design, while respecting the thoughts and opinions of their peers.
• Adaptable, proactive and results-oriented, capable of delivering solutions efficiently and meeting tight deadlines.
• Proven ability to communicate and collaborate effectively with engineers across all platforms and non-engineering stakeholders alike.
• Comfortable working remotely and collaborating asynchronously with teammates in different timezones and from different backgrounds.

The Extras

Working at Slice comes with a comprehensive set of benefits, but here are some of the unexpected highlights:

• Access to healthcare plans
• Flexible working hours
• Generous time off policies
• Employee wellbeing allowance
• Market leading maternity and paternity schemes

The Hiring Process

Here’s what you can expect from our hiring process if your candidacy progresses smoothly. We move quickly and strive for a fast turnaround from the final interview to the offer.

• Application
• 30-minute introductory meeting
• 90 minute Live Coding Interview & 60 minute Technical Interview
• 30-minute Hiring Manager meeting
• Offer!

Pizza brings people together. Slice is no different. We’re an Equal Opportunity Employer and embrace a diversity of backgrounds, cultures, and perspectives. We do not discriminate on the basis of race, colour, gender, sexual orientation, gender identity or expression, religion, disability, national origin, protected veteran status, age, or any other status protected by applicable national, federal, state, or local law. We are also proud members of the Diversity Mark NI initiative as a Bronze Member.

Privacy Notice Statement of Acknowledgment

When you apply for a job on this site, the personal data contained in your application will be collected by Slice. Slice is keeping your data safe and secure. Once we have received your personal data, we put in place reasonable and appropriate measures and controls to prevent any accidental or unlawful destruction, loss, alteration, or unauthorised access. If selected, we will process your personal data for hiring /employment processes, as well as our legal obligations.

If you are not selected for the job position and you have given consent on the question below (by selecting "Give consent") we will store and process your personal data and submitted documents (CV) to consider eligibility for employment up to 365 days (one year). You have the right to withdraw your previously given consent for storing your personal data and CV in the Slice database considering eligibility for employment for a year. You have the right to withdraw your consent at any time.

For additional information and / or exercise of your rights to the protection of personal data, you can contact our Data Protection Officer, e-mail: privacy@slice.com

Why Valtech? We’re the experience innovation company - a trusted partner to the world’s most recognized brands. To our people we offer growth opportunities, a values-driven culture, international careers and the chance to shape the future of experience. 

The opportunity

At Valtech, you’ll find an environment designed for continuous learning, meaningful impact, and professional growth. Whether you're pioneering new digital solutions, challenging conventional thinking or building the next generation of customer experiences, your work will help transform industries. 

We are proud of: 

• The work we do and the innovation we drive 
• Our values of share, care and dare 
• A workplace culture that fosters creativity, diversity and autonomy 
• Our borderless, global framework, which enables seamless collaboration 

The role  

Valtech is looking for a Flutter Lead Developer to shape our cross-platform mobile and web application landscape. In this role, you will own the technical strategy, architecture, and delivery of scalable, high-performing Flutter applications that power digital experiences across our business. Working at the intersection of design, development, and product, you’ll lead a cross-functional team of developers and testers, define best practices, and transform ideas into elegant, responsive, and maintainable apps. You will play a key role in driving technical excellence and Flutter adoption, while mentoring others and contributing to a culture of innovation and quality.

Role responsibilities

• Lead Flutter mobile app development across Android / iOS.
• Focus on best engineering practices for quality, clean code, testing & observability.
• ⁠Architect scalable, maintainable, and performant mobile solutions.
• Mentor and guide Flutter developers; conduct code reviews.
• Collaborate with product, design, and backend teams.
• Ensure code quality, testing, and CI/CD integration.
• Stay updated with Flutter/Dart trends and best practices.
• Manage technical risks and project timelines.

Must have qualifications

To be considered for this role, you must meet the following essential qualifications: 

• 7+ years of total development experience, with at least 3+ years in Flutter development. 
• Strong knowledge of data structures, modern design patterns, and best practices in object-oriented software engineering. 
• The ability to write clean and neat code that is easy to maintain. 
• The ability to cover all (or almost all) your work with tests. 
• Understanding the principles of user interface design. 
• Expert knowledge of the Dart language.
• Experience developing native applications (Android/iOS) will be a plus. 
• Knowledge of development and configuration tools (Git, Jira, Jenkins, etc.). 
• Experience with RESTful APIs to connect to back-end services. 
• Knowledge of modern architectural patterns in mobile development (BLoC, MVVM) and the principles of functional programming. 
• Understanding the principles of DRY and SOLID principles. 
• Experience in creating multi-module projects.
• Advanced level of English, both written and verbal.

If you do not meet all the listed qualifications or have gaps in your experience, we still encourage you to apply. At Valtech, we recognize that talent comes in many forms, and we value diverse perspectives and a willingness to learn. 

Commitment to reaching all kinds of people 

We design experiences that work for all kinds of people - and that starts with our own teams. At Valtech, we’re intentional about building an inclusive culture where everyone feels supported to grow, thrive and achieve their goals. No matter your background, you belong here. Explore our Diversity & Inclusion site to see how we’re creating a more equitable Valtech for all. 

The benefits  

• Private health insurance
  We hope you will never need it, but nevertheless, we offer private health insurance to all our employees.

• Education program
  We never stop learning, that’s why we offer our employees an educational program with training and certification.

• Wellbeing program
  We all deserve to live a healthy and well-balanced life. It's not an option, it's a necessity!

• Free beverages
  Enjoy free coffee, drinks, and snacks at work, or join one of our famous company dinners.

• Events
  We enjoy spending time together, not only at work. Ski trips, carting, laser-tag, wine tasting, picnics, cooking classes… you name it – we’ve done it! There are plenty of cool events to join and to get to know your colleagues.

• Competitive conditions
  Besides a competitive salary and 24 days of vacation, you will join annual company events with the whole team.

• Challenging projects
  Ready for a challenge? We guarantee you'll find challenging projects at Valtech!
  
  
• Cool colleagues
  What's the most important thing in a job? Cool colleagues with whom you spent most of the time during the week. We have a lot of them!
  
  
• Honest feedback
  Honesty, openness and respect are among our core values. We encourage an open feedback culture in order to build trust and grow together.

Your application process

Once you apply, our Talent Acquisition team will review your application. Your CV should cover key information on relevant experiences and expertise. We do not require information such as age, gender, marital status, or a headshot in your application. We review all candidates based on skills, experience, and potential.

⚠️ Beware of recruitment fraud!

We are committed to inclusion and accessibility. If you need reasonable accommodations during the interview process, please either indicate it in your application or let your Talent Partner know. 

About Valtech

Valtech is the experience innovation company that exists to unlock a better way to experience the world. By blending crafts, categories, and cultures, we help brands unlock new value in an increasingly digital world. 

At the intersection of data, AI, creativity, and technology, we drive transformation for leading organizations, including L’Oréal, Mars, Audi, P&G, Volkswagen Dolby, and more. 

At Valtech, we don’t just talk about transformation. We make it happen. Our people are the heart of our success, and we foster a workplace where everyone has the support to thrive, grow and innovate. 

Are you ready to create what’s next? Join us.

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

MSA is a highly multi-disciplinary group started in 2019 to tackle difficult mail delivery, spam, abuse, and account security problems that impact the Proton ecosystem. We built sophisticated systems from scratch that combine human intelligence and machine learning to make tens of millions of realtime or asynchronous decisions each day. Our custom systems have reduced spam filter misclassifications by over 60%, blocked millions of abusive bulk signups, protected hundreds of thousands of users from account compromise by attackers, and mitigated hundreds of DDoS attacks. In the last few years, we have also been building complicated new products, including launching Wallet, Lumo AI, and Meet. We are the main group at Proton working on AI. In order to move fast with limited resources, we are organized into autonomous teams responsible for the whole system, with expertise across infrastructure, data storage, backend, web and mobile apps, machine learning, security and operational excellence. We are looking for humble, mission-driven, systems-thinking people who want to make a big impact in a startup environment.

What you will do

MSA builds and operates many services responsible for different domains. You will:

• work with other engineers and analysts to design, build, and operate these systems
• work on special user-facing features involving frontend and backend software development
• You will have the opportunity to play Product or Project Managers roles and lead the whole planning and development process
• be responsible for the operational excellence of the systems/features and their interaction with other systems
• You may work on MSA's custom systems written in Python or on the main Proton API written in PHP or on Proton Web apps written in React or even on native iOS and Android mobile apps

Job requirements

• Deep experience with backend development (Python, PHP, or Go)
• Experience with frontend design and development (JavaScript, React, Typescript, or jQuery)
• Experience building complex production systems
• Experience with data processing and storage (MySQL, MongoDB, Redis, Kafka, Elastic, Ceph, ClickHouse)
• Able to work autonomously and lead the whole development process, from design to QA
• Experience with AI tools and AI agents
• Excellent English communications, both written and spoken

Bonus points for: 

• experience with machine learning and real-time prediction systems
• experience with iOS or Android app development
• experience with managing Linux servers, including infrastructure as code (Puppet, Ansible) and containerization

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.

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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 

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