> Markdown version of [/jobs/ext/4708548-medior-backend-developer](https://www.wearedevelopers.com/jobs/ext/4708548-medior-backend-developer). Every page supports `.md` or `Accept: text/markdown`. Links point to the HTML versions so they work for humans too. Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md).

---

# Medior Backend Developer

- **Company:** Lefebvre Sdu
- **Location:** Netherlands
- **Experience:** Experienced
- **Salary:** €5,500
- **Contract:** Permanent contract
- **Skills:** LangGraph Framework, Application Programming Interfaces (APIs), Artificial Intelligence, Software Quality, DevOps, Github, PostgreSQL, MongoDB, Software Product Management, Web Services, Backend, Fastapi, Graphql, Front End Software Development
- **Published:** November 14, 2026
- **Apply:** https://startup.jobs/backend-developer-python-java-lefebvre-sdu-10769932

## About the Role

* You pick up your work independently. You don't need much guidance, but you know when to involve a colleague.
 * You have opinions and you are not afraid to share them.
 * And you enjoy working with AI specialists on a product that is still very much in development.
 * At least 3 years of experience building Python applications that run in production and are actually used by customers.
 * Experience with FastAPI and Pydantic. Experience with LangChain or LangGraph is a plus.
 * You have built production-grade APIs that work reliably for real users.
 * You work independently within a team and don't need hand-holding.
 * Knowledge of Postgres, GraphQL or MongoDB is a plus.
 * Some DevOps knowledge is nice to have, for example working with GitHub Actions and Helm.

## Description

Lawyers and tax advisors ask a question in GenIA-L and get a reliable answer. That answer is what they see. What you build is everything needed to make it happen: the backend. These are the systems and connections that keep our AI product fast, secure and reliable. You join the AI team and work with our AI engineers every day. They make the product smart; you make sure that intelligence actually reaches the user. After six months, you know the code well and have shipped several new features. After that, you choose the direction you want to grow in: more towards AI, for example by improving the quality of our AI answers, or more towards DevOps, for example by improving how we automatically test and release software.

 * You build and maintain the backend of our main AI product, together with our AI engineers.
 * You build APIs and services: the connections that let the different parts of the platform talk to each other.
 * You keep an eye on code quality and make sure we follow good practices and standards.
 * You monitor and maintain our live applications and fix problems when something goes wrong.
 * You bring your own ideas on how to improve the product and the way we work.
 * You are proactive, enthusiastic, and take initiative.
 * You communicate clearly and confidently, conveying information in a concise and engaging manner., You join the AI team with one other backend engineer, three AI engineers and a Product Owner. You also work closely with the search team, the frontend team and our backend and AI leads. You report to our Lead Backend Engineer. You get a lot of freedom and room for your own opinions and ideas, in a fun team with a good work-life balance. And you can grow into a Senior or Lead Backend Engineer role.