Anyone else been burned by federated GraphQL schema changes breaking staging? I wanted to share this tutorial on using WunderGraph feature flags + isolated test environments to validate schema evolution safely. The approach is pretty clever - uses feature flags to route specific requests to updated subgraphs while keeping baseline traffic untouched. Real step-by-step implementation with Kubernetes. Might save you some headaches: https://www.signadot.com/blog/using-sandboxes-with-wundergraph