AI-Generated End-to-End API Tests: An Experience Report in Legacy Modernization

Legacy modernization projects remain particularly risky, even in 2026. What can AI bring to the table?

In this session, we share a concrete experience report from an AI-powered end-to-end test generation project, designed to secure the refactoring of complex APIs handling €500M in annual revenue. We'll demonstrate how we designed an AI workflow (agents with MCP) to reliably and repeatably regenerate API tests that compare complex JSON payloads exceeding 200 KB.

Moreover, through a short demo, we'll show how the developer role is evolving toward designing prompts that generate prompts that generate code, the value of maintaining strict code quality standards, and how sub-tasks with dedicated contexts can reduce AI costs over time. And because we're in DDD Europe, we'll connect what we learned to Domain-Driven Design practices!