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 OpenShift

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