🛰 NATS Visualizer
Four simulated microservices publish events over NATS. Watch Core pub/sub, JetStream persistence, and KV health heartbeats update in real time.
recv().via.events.*). Fire-and-forget: if you kill one of these services its simulator stops and any events published while it is offline are gone forever.VIAEVENTS stream captures every message in memory. The durable consumer tracks its last-delivered sequence across subscribe/unsubscribe cycles — a revived subscriber never misses a message.$KV.viahealth.{service} every 2 s. Guaranteed services always heartbeat (only the consumer is paused); best-effort services stop heartbeating when killed. The health grid reads KV age.Coroutine::create()) prevents race conditions.via.events.*
auth, inventory
VIAEVENTS
253189 msgs
ui-orders, ui-payments
ACK guaranteed
viahealth
heartbeats
via.events.*
253188 ✓
🎯 Actions
kill-orders / kill-payments
Pauses the JetStream durable consumer (unsubscribes from the deliver inbox). Simulator keeps publishing; NATS buffers un-ACKed messages. Health tile stays green — the service is still alive, only the consumer is paused.
kill-auth / kill-inventory
Stops the event simulator entirely. Events are silently dropped — Core pub/sub has no persistence. Health tile flips to DOWN after 8 s of silence.
revive-{service} (×4)
Guaranteed services: re-subscribes to the deliver inbox; JetStream immediately delivers all buffered events in a burst. Best-effort: restarts the simulator and publishes a fresh KV heartbeat.
👁 Views
mission_control.html.twig
Flow diagram piping services → NATS → browser, service kill/revive cards with delivery-type badges, NATS topology with health tiles, and a live event stream.