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# Backend Engineer

- **Company:** CodeGuild
- **Location:** Amsterdam, Netherlands
- **Experience:** Expert
- **Salary:** €7,500.0 - €9,167.0
- **Contract:** Permanent contract
- **Skills:** Software System Penetration Testing, Big Data, Distributed Systems, Open Source Technology, Multi-Agent Systems, Backend, Agentic-AI, Event Driven Architecture, Kubernetes, Apache Kafka
- **Published:** October 22, 2026
- **Apply:** https://www.codeguild.nl/en/software-developer-jobs-netherlands/senior-backend-engineer-amsterdam-offensive-security-1066710#apply

## About the Role

* Real offensive security experience. Pentesting, red teaming, bug bounty, CVEs, serious CTF work: you have been on the attacking side and you can show it.
 * Hands-on Kubernetes experience in production. You have run real workloads on it yourself, not only deployed to it.
 * 6+ years of professional experience, including senior backend work on distributed systems at scale
 * Experience operating production systems, with the battle scars to prove it
 * The initiative to come up with ideas, write them down and then build them

The offensive experience and the production Kubernetes experience are both hard requirements.

Nice to have, none of them a dealbreaker:

 * Go, Kafka or other event-driven systems
 * Agentic AI or autonomous agents
 * Systems under extreme load and large databases
 * Open source contributions, especially security or recon tooling
 * Experience with a European cloud provider

## Description

They are looking for a Senior Backend Engineer who still thinks like a hacker. There is always a lot of room for your own ideas, and that is the core of the role: what else can we automate in scanning and testing, which attack paths are we not covering yet. You write an idea down, and then you build it yourself.

Right now they have the chance to work agentic AI much deeper into their systems, and that is where you can really sink your teeth in. Parts of the agentic attack system already exist, other parts still need to be integrated. The hard question is how to make agents that run multi-step attacks reliable, at scale, in production.

The data volumes are serious. The team has run into the limits of Kubernetes and the cloud vendors before. So distributed systems questions are daily work: what happens when a task runs twice, when a dependency times out halfway, when a retry is not safe, when what you know about a target quietly becomes incorrect state.

You work closely with the cloud and infra teams to get the most out of the platform, and you deploy and monitor your own code. Engineering works in guilds, and the codebase is run in an open source style, so other teams, and agents, can open pull requests and contribute. The language is Go. If you have not written much Go yet but bring the rest, you get the chance to go deep in it here.