Back-end Developer

The job

Every day, Twikey processes the recurring payments of thousands of companies: direct debits, card payments, payment links. Behind every transaction is a customer who counts on the money arriving correctly, exactly once and on time. That's the system you'll help build.

You'll work in a small development team on the core of the platform: 3 developers, 2 testers and a technical team lead who shields you from noise, not a manager layer. No tickets thrown over the wall: you design, build, help test and follow up in production.

What you'll work on

• Payments that must never be duplicated or lost. Retries, concurrent processing and external systems that don't always do what they promise: you make sure the outcome is still right.
• Integrations with banks, software houses and large companies. You build and maintain APIs and integrations, and give partners technical support during their integration.
• Growth. Volume goes up every year. You find the bottlenecks in queries, data model and processing before they become a problem.
• Production. When something goes wrong, you find out why, fix it and make sure it doesn't happen again. During working hours, that is: developers don't do on-call.

Our stack

Java, Spring and Go on Linux, PostgreSQL and a lot of APIs. We choose technology for what works, not for what's trendy. Got a better idea? We'd like to hear it.

How we look at AI

AI writes a lot of code these days, including at Twikey. What matters is whether you can judge if that code is right. You treat AI output like a pull request from a junior: read it, test it, question it. Only then does it go to production.

What are we looking for in you?

• You have several years of experience as a back-end developer with Java and Spring. Go is a plus, or you pick it up quickly.
• You understand databases (PostgreSQL, in our case): not just how to use them, but how they work. You know what a query does, when an index helps and where transactions begin and end.
• You understand concurrency and think in failure modes: what happens if this comes in twice at the same time, or fails halfway through?
• You've been through a production incident and can explain what went wrong, how you found it and what you changed structurally afterwards.
• You can name trade-offs and defend your choices. You can also tell us what you'd do differently today.
• You write code that is readable, testable and maintainable, and you like giving and receiving critical review.
• You work independently and take ownership, from design to follow-up in production.
• You're fluent in English. Dutch is an asset.
• You're based in a time zone within one hour of CET, so your working day overlaps with the team's for daily stand-ups and close collaboration.
• Experience with payments, banks or fintech is a plus, not a requirement. So is a degree: what you've built counts for more.

Twikey offers you:

• Direct impact on a product used daily by thousands of companies, in a small team where your ideas reach production quickly.
• The room to experiment, to challenge and to improve. And we expect you to really take that room.
• A competitive salary matched to your experience.
• More than 35 colleagues in an open culture of critical dialogue, and a monthly Friction Hunter Trophy for whoever made the biggest difference.