Event Lab is a live, interactive Kafka load simulator. Drag a slider and watch producer throughput, per-partition consumer lag, and backpressure react in real time. Built on Redpanda, deployed on Fly.io, and rate-capped so a public demo stays cheap to run. Architecture write-up and full source on GitHub.

A runnable demo of the pattern a stateless routing proxy needs when it sits in front of a federated MCP hub it doesn't own: discover tools from the hub at runtime, cache them for a short TTL instead of polling before every dispatch, and force the LLM's tool-choice into an enum of only the currently-live names, eliminating hallucination at the API boundary. Includes a mock Fastify hub, two safety guards, and a CLI script that mutates the hub live while the router adapts with no code change. Full source on GitHub.