Senior Backend Engineer - Money Transfers

<p><strong>SumUp</strong> builds simple, affordable financial tools that help over 4 million small businesses across 37 markets get paid, manage their money, and grow. Beyond card payments, we offer a full suite of financial products - business banking, lending, invoicing, and money transfers - giving merchants everything they need in one place.&nbsp;</p>
<p>Our <strong>Transfers Excellence squad</strong> sits within SumUp's <strong>Global Bank</strong>, and owns the core services that power how merchants and consumers move money. E.g. IBAN-based transfers, money in and out, and peer-to-peer payments via the SumUp consumer app. With the high volume transfers per hour across our European markets. That means reliability isn't a nice-to-have - it's the baseline for us. Right now, the team is replacing a set of market-specific implementations with a single, unified global transfer platform that will serve Europe, the UK, Brazil, Chile, and eventually the US and Canada.&nbsp;</p>
<p>Join our team and contribute directly to platform-level architecture that will shape how SumUp moves money at scale - work that directly impacts millions of small businesses every day.<br><br>Our tech stack includes Kotlin, Java, Go, a bit of Elixir, AWS, Kafka, PostgreSQL, and Kubernetes, supported by a strong observability toolchain with Prometheus, Grafana, and Honeycomb. We also actively use AI‑assisted development tools such as Cursor, GitHub Copilot, and others.</p>
<p data-pm-slice="1 1 []">🎥 Get a feel for life in our <a class="text-primary underline cursor-pointer" href="https://www.youtube.com/watch?v=9DG64C3moeQ" target="_blank">Berlin office</a>.</p>
<h2><strong>What you'll do</strong></h2>
<ul>
<li>Build and maintain backend services that sit at the heart of SumUp's transfer infrastructure, taking end-to-end ownership from development through to observability, testing and production support</li>
<li>Contribute to the migration from market-specific services toward a unified global transfer platform, working across a mix of active services and legacy systems being decomposed</li>
<li>Raise well-scoped pull requests, conduct thorough code reviews, and help maintain high standards of code quality and test coverage across the team</li>
<li>Participate in incident reviews and the on-call rotation, taking accountability for the reliability of the services you build</li>
<li>Contribute to the technical roadmap by participating in architectural discussions and proposing solutions for complex, distributed systems challenges</li>
<li>Apply AI tooling to accelerate your own engineering workflows and contribute to raising the team's overall AI literacy</li>
</ul>
<h2><strong>You'll be great for this role if…</strong></h2>
<ul>
<li>Solid experience as a Backend Software Engineer in modern languages (e.g. Kotlin, Go, Java, etc.). Kotlin is the team's primary language and we also work with Java, Golang, and Elixir.</li>
<li>Solid understanding of distributed systems and event