Senior iOS Engineer

About Tandem Tandem is the leading global language learning community, where more than 30 million members from over 200 countries practice languages together. The concept of learning from each other is not only an integral part of the Tandem community but it is also at the heart of our everyday lives at Tandem. This shared connection through learning helps us to grow and enhance the language journeys of our members. We are based in Berlin and are backed by top European investors. We are highly international and driven by a shared passion for languages, technology, and culture. Together, we are on a mission to build a product that not only teaches a new skill but also encourages meaningful cross-cultural conversations. As an Senior iOS Engineer you will work as part of an agile, cross-functional team of designers and engineers to architect, develop and maintain the Tandem iOS app. Your role will focus on strengthening and scaling our current architecture to help Tandem keep shipping high-quality, meaningful features that our members love. Your role will be to: Mature and modernize our existing iOS codebase. Build and ship new product features. Ensure we take full advantage of iOS platform capabilities. Help shape technical decisions and drive engineering excellence. You are the right fit for the role if you: Have 5+ years of iOS development experience with Swift (and ideally Objective-C) Have strong knowledge of the iOS ecosystem: UIKit, SwiftUI, etc. Are experienced with reactive programming and building scalable, maintainable solutions (Clean Architecture, modularization, design patterns) Have worked on production apps at scale (500k+ users) and care about performance and reliability Can lead technical design discussions, act as the iOS expert in the room, and provide constructive feedback Have experience with CI/CD and enjoy improving engineering practices Communicate clearly, collaborate well across teams, and are curious about new technologies What would make your application stand out: Experience building realtime chat and media services Experience with Kotlin Multiplatform Experience with iterative design and working with agile cross-functional teams Experience implementing and optimizing iOS accessibility features The benefits Passion for languages: We’re a team of 30 people speaking 20 languages fluently between us. For those wanting to improve their German (or Denglisch!), you can join one of our German classes on us. Take a deep dive: As a Tandem team member, we’ll give you a budget for up to 6 “Deep Dive Days” per year. Pick a topic you’ve always wanted to explore for your professional development that has never made it out of your backlog. Then book a cabin in the woods or whatever matches your individual learning style. Teams who train together, stay together: We offer Urban Sports Club gym memberships to boost our team’s physical and mental health. If you prefer, we can contribute to your monthly public transport ticket instead. It takes a team to Tandem: Bonding with our teammates outside of our normal work routine is important to us. We organize regular team events: from day trips to monthly lunches, summer BBQs, and movie nights. Balance matters: Life isn’t just about work. We know when to snooze Slack notifications, recharge our batteries, and take time out for our personal hobbies. As home office has become the new normal for some of us, it’s even more important to be able to switch off from work and relax. Modern family: As part of our family-friendly company philosophy, we embrace flexible working hours, welcome families to our events, and love for our kids to visit the office and get a taste of life at Tandem. Relocation without the stress: If you’re looking to relocate to Berlin, we’re ready to assist you with the infamous German bureaucracy. Many of us have been through it before, so we have plenty of tips to share. You’ll feel settled in no time. Hybrid by design: We’re all about embracing a flexible, modern way of working. That’s why we focus on a hybrid approach—balancing time between our vibrant Berlin-Mitte office and the comfort of your home. It’s the best of both worlds, and we’ll support you in creating the perfect setup for this dynamic way of working.