Full-stack (Kotlin) Engineer (m/f/d) - Team Payments

Company: Flix
Location: Berlin, Berlin, Germany

<p style="line-height: 1.4;">At Flix, we offer a tech-driven environment where innovation meets real-world impact, with competitive pay, strong growth opportunities, and a culture of collaboration and ownership.  </p>
<p>As a <strong>Full-stack Engineer</strong> with a strong backend focus (Kotlin) you will help us build the future of payments for green and smart mobility. </p>
<p>You'll join our <strong>Payments Team</strong> - the heart of our checkout experience - as part of our Demand Division. Your work will directly impact how millions of people pay, how quickly their transactions are processed, and how much revenue we generate. We continuously work to improve payment authorization and conversion rates, increase payment efficiency and revenue protection, and ensure data reliability. At the same time, we're integrating local payment methods across different markets and tackling complex engineering challenges along the way. </p>
<p>We build our core services using <strong>Kotlin and Spring Boot</strong>, and our interfaces with <strong>TypeScript</strong><strong> and React.js</strong>. We also maintain some legacy <strong>PHP</strong> systems — you don't need to love it, but you should be open to working with it when needed. </p>
<p>Our Payments Team consists of four backend engineers, two frontend engineers and an Engineering Manager. </p>
<p><strong data-renderer-mark="true">About the Role</strong></p>
<ul>
<li style="font-size: 12pt;">Build the systems that move money fast, safely, and at scale </li>
<li style="font-size: 12pt;">Design and ship features used by millions of users </li>
<li style="font-size: 12pt;">Write clean, tested, production-ready code </li>
<li style="font-size: 12pt;">Own features from idea to release </li>
<li style="font-size: 12pt;">Work closely with business, UX, frontend, and backend engineers </li>
<li style="font-size: 12pt;">Review code, pair program, and ship often </li>
<li style="font-size: 12pt;">Improve existing systems and clean up legacy code </li>
</ul>
<p><strong data-renderer-mark="true">About You</strong></p>
<ul>
<li style="font-size: 12pt;">3-4 years of experience building backend or full-stack web applications, including at least 2 years working with Kotlin in a commercial setup </li>
<li style="font-size: 12pt;">Some experience with frontend development with JavaScript/Typescript and any modern framework (React.js, Vue.js, Angular)  </li>
<li style="font-size: 12pt;">Open to working with PHP in legacy systems when needed - prior experience is not required, the team will support your learning</li>
<li style="font-size: 12pt;">Strong object-oriented programming skills with a focus on clean architecture and maintainable design </li>
<li style="font-size: 12pt;">Solid experience working with relational databases </li>
<li style="font-size: 12pt;">Hands-on experience with automated testing (unit, integration, component or UI)</li>
<li style="font-size: 12pt;">Hands-on experience deploying applications to production environments using CI/CD pipelines </li>
<li style="font-size: 12pt;">Clear written and spoken English communication skills </li>
<li style="font-size: 12pt;">A collaborative, team-first mindset </li>
</ul>
<p><strong>Nice to have - we'll support you in developing these skills if needed: </strong></p>
<ul>
<li style="font-size: 12pt;">Containerization and orchestration tools such as Docker and k8s </li>
<li style="font-size: 12pt;">Familiarity with event-driven architectures and messaging systems (e.g., Kafka) </li>
<li style="font-size: 12pt;">Exposure to AWS or other cloud platforms </li>
</ul>
<p style="line-height: 1.4;">We recognize that everyone carries a unique set of valuable skills and experiences. If you think you could have an impact even though you don't meet 100% of the requirements, we still encourage you to apply. We want to hear from you!  </p>
<p><strong>What We Offer</strong></p>
<ul>
<li data-renderer-start-pos="11445"><strong data-renderer-mark="true">Travel perks</strong>: 12 free Flix vouchers + 12 discount vouchers for friends & family. </li>
<li data-renderer-start-pos="11530"><strong data-renderer-mark="true">Work from (M)Anywhere</strong>: Depending on your role, work from another location for up to 60 days per year. </li>
<li data-renderer-start-pos="11636"><strong data-renderer-mark="true">Hybrid work model</strong>: We are an office-first company, but we offer flexibility to balance work and life. </li>
<li data-renderer-start-pos="11742"><strong data-renderer-mark="true">Wellbeing support</strong>: Access confidential 1:1 counselling, courses, and stress management for yourself and up to four family members. </li>
<li data-renderer-start-pos="11877"><strong data-renderer-mark="true">Learning & Development</strong>: Take advantage of language classes, training courses, and expert-led sessions to grow your skills. </li>
<li data-renderer-start-pos="12004"><strong data-render…