Wiki Kafka
Live Wikipedia edits, streamed through Kafka and visualized in real time.
Built to demonstrate a production-shaped streaming pipeline end to end: ingestion, stateful stream processing, and monitoring wired together the way a real system needs them, not a toy consumer loop.
Kafka Streams over a plain consumer
Rolling per-domain edit aggregates need a state store and fault tolerance that a bare consumer loop doesn't give you for free. Kafka Streams provides both.
Observability from day one
Prometheus, Grafana, and Alertmanager are part of the initial docker-compose stack, not bolted on after something broke.