Senior Backend Developer

We’re looking for a Senior Backend Developer who challenges assumptions, builds with intention, and thrives in a fast-moving, AI-driven environment. At 3ap, engineers own their work end-to-end. Our teams run on separate projects but solve hard problems together, share what they learn, and call out bad assumptions, including their own.

What we need: 5+ years of experience building backend systems with Java (Spring) and its ecosystem Track record of shipping production-ready applications, including ones that integrate LLMs and unstructured data Strong REST API design and integration experience, and solid understanding of microservices architecture Hands-on with Docker, Kubernetes, Jenkins, and Open.

Shift Rigorous about testing and validation, especially where AI outputs are non-deterministic You think about the full product, not just your layer. A bad integration can sink a good solution You’re an exceptional communicator, comfortable talking to designers, frontend engineers, product managers, and stakeholders, and presenting your work to non-technical people You’ve gone deep into AI tools, not just used them casually, and know how to get real production value out of them, while treating AI output as a draft, not a deliverable You’ve used GitHub Copilot, Claude, or similar in your actual workflow, and you build guardrails around what they produce You don’t stop at “it works.

” You look for the flaw in the logic before someone else finds it in production You pick up new tools fast. The AI landscape shifts week to week, and waiting to learn something familiar isn’t an option University degree in CS or equivalent Fluent English Useful, but not required: Node.js, TypeScript, PostgreSQL, or MongoDB Frontend experience with React, Angular, or Vue CI/CD and DevOps hands-on experience Familiarity with API tools like Postman or Insomnia Prompt engineering or multi-step AI workflows Comfort and openness to working with Python.

Many modern AI tools and frameworks are built with Python at their core, so a willingness to learn and use it is important Background in insurance or finance Any German What you get: A team of 60+ professionals in a people-first culture, flat structure, and no bureaucracy Work that uses current technology, including AI in production Flexible hours, hybrid work 25 vacation days + 2 extra 3ap holidays Private pension, private health insurance, 24/7 accident insurance Maternity and paternity leave support Team events and an employee referral program