Your dead letters, handled before the 3 a.m. call.

A RabbitMQ, Warren and three dead-letter queues with real dead letters. Only Docker needed.

1. 1
   docker-compose.try.ymlCopy

   Copy it and save it as docker-compose.try.yml. Read it first if you like: a RabbitMQ, a one-off step that fills three queues with dead letters, and Warren.

   # Try Warren in a minute: a RabbitMQ, Warren next to it, and dead letters to look at.
   #
   #   docker compose -f docker-compose.try.yml up -d      →  http://localhost:8080, sign in as admin / admin
   #   docker compose -f docker-compose.try.yml down -v    →  everything gone again
   #
   # The seed step fills a few queues the way real consumers would: orders rejected by the consumer,
   # invoices that expired while nobody listened, shipping labels a Spring consumer republished with its
   # exception. Open orders.dlq, look at why they died, select a few and replay them. Nothing here
   # touches a broker of your own; the RabbitMQ management UI is on http://localhost:15680 (warren / warren), off the
   # default port so it never collides with a RabbitMQ you already run.
   # Ports taken? TRY_WARREN_PORT=8081 TRY_RABBIT_UI_PORT=15690 docker compose -f docker-compose.try.yml up -d
   name: warren-try
   
   services:
     rabbitmq:
       image: rabbitmq:4-management
       environment:
         # guest may only sign in from localhost; Warren and the seed step come from their own containers
         RABBITMQ_DEFAULT_USER: warren
         RABBITMQ_DEFAULT_PASS: warren
       ports:
         - "${TRY_RABBIT_UI_PORT:-15680}:15672"
       healthcheck:
         test: ["CMD", "rabbitmq-diagnostics", "-q", "check_port_connectivity"]
         interval: 5s
         retries: 30
   
     # Declares the demo topology and dead-letters messages through the management API, then exits.
     # Runs once: when orders.dlq already holds messages it leaves them alone.
     seed:
       image: curlimages/curl:8.11.1
       depends_on:
         rabbitmq: { condition: service_healthy }
       restart: "no"
       entrypoint: ["/bin/sh", "-c"]
       command:
         - |
           set -e
           api() { curl -sf -u warren:warren -H 'content-type: application/json' -X "$$1" "http://rabbitmq:15672/api$$2" $${3:+-d "$$3"} > /dev/null; }
           if curl -sf -u warren:warren http://rabbitmq:15672/api/queues/%2F/orders.dlq | grep -q '"messages":[1-9]'; then echo "already seeded"; exit 0; fi
   
           # orders: the consumer rejects, the broker dead-letters to orders.dlq
           api PUT /exchanges/%2F/orders '{"type":"topic","durable":true}'
           api PUT /exchanges/%2F/orders.dlx '{"type":"fanout","durable":true}'
           api PUT /queues/%2F/orders.dlq '{"durable":true}'
           api PUT /queues/%2F/orders.process '{"durable":true,"arguments":{"x-dead-letter-exchange":"orders.dlx"}}'
           api POST /bindings/%2F/e/orders.dlx/q/orders.dlq '{"routing_key":""}'
           api POST /bindings/%2F/e/orders/q/orders.process '{"routing_key":"order.*"}'
           # billing: invoices with a TTL, nobody consumes, they expire into billing.invoice.dead
           api PUT /exchanges/%2F/billing '{"type":"direct","durable":true}'
           api PUT /exchanges/%2F/billing.dlx '{"type":"fanout","durable":true}'
           api PUT /queues/%2F/billing.invoice.dead '{"durable":true}'
           api PUT /queues/%2F/billing.invoice '{"durable":true,"arguments":{"x-message-ttl":2000,"x-dead-letter-exchange":"billing.dlx"}}'
           api POST /bindings/%2F/e/billing.dlx/q/billing.invoice.dead '{"routing_key":""}'
           api POST /bindings/%2F/e/billing/q/billing.invoice '{"routing_key":"invoice"}'
           # shipping: a Spring consumer gave up and republished to the DLQ itself (RepublishMessageRecoverer)
           api PUT /exchanges/%2F/shipping '{"type":"direct","durable":true}'
           api PUT /queues/%2F/shipping.label '{"durable":true}'
           api PUT /queues/%2F/shipping.label.dlq '{"durable":true}'
           api POST /bindings/%2F/e/shipping/q/shipping.label '{"routing_key":"label"}'
   
           customers="ACME Northwind Contoso Initech Globex"
           i=0
           for c in $$customers $$customers $$customers $$customers; do
             i=$$((i + 1)); id=$$((4700 + i))
             if [ $$((i % 4)) -eq 0 ]; then err='Customer '$$c' is locked'; type=com.acme.orders.CustomerLockedException
             else err='Timeout calling inventory after 5000 ms'; type=java.net.SocketTimeoutException; fi
             api POST /exchanges/%2F/orders/publish "{\"routing_key\":\"order.created\",\"payload_encoding\":\"string\",\"payload\":\"{\\\"orderId\\\":$$id,\\\"customer\\\":\\\"$$c\\\",\\\"total\\\":$$((i * 37)).50}\",\"properties\":{\"message_id\":\"order-$$id\",\"content_type\":\"application/json\",\"headers\":{\"x-exception-type\":\"$$type\",\"x-exception-message\":\"$$err\"}}}"
           done
           api POST /queues/%2F/orders.process/get '{"count":20,"ackmode":"reject_requeue_false","encoding":"auto"}'
           # three orders still on their way, so orders.process is not empty
           for id in 4801 4802 4803; do
             api POST /exchanges/%2F/orders/publish "{\"routing_key\":\"order.updated\",\"payload_encoding\":\"string\",\"payload\":\"{\\\"orderId\\\":$$id}\",\"properties\":{\"message_id\":\"order-$$id\",\"content_type\":\"application/json\"}}"
           done
   
           for n in 1 2 3 4 5 6; do
             api POST /exchanges/%2F/billing/publish "{\"routing_key\":\"invoice\",\"payload_encoding\":\"string\",\"payload\":\"{\\\"invoiceNo\\\":\\\"2026-10$$n\\\",\\\"amount\\\":$$((n * 120))}\",\"properties\":{\"message_id\":\"inv-2026-10$$n\",\"content_type\":\"application/json\"}}"
           done
   
           for n in 1 2 3 4; do
             api POST /exchanges/%2F/amq.default/publish "{\"routing_key\":\"shipping.label.dlq\",\"payload_encoding\":\"string\",\"payload\":\"{\\\"shipmentId\\\":\\\"SH-90$$n\\\",\\\"carrier\\\":\\\"DHL\\\"}\",\"properties\":{\"message_id\":\"label-90$$n\",\"content_type\":\"application/json\",\"headers\":{\"x-original-exchange\":\"shipping\",\"x-original-routing-key\":\"label\",\"x-exception-message\":\"Carrier API answered 503 Service Unavailable\",\"x-retry-count\":3}}}"
           done
           echo "seeded: 20 in orders.dlq, 6 expiring into billing.invoice.dead, 4 in shipping.label.dlq"
   
     warren:
       image: ghcr.io/viba88/warren:0.17
       depends_on:
         rabbitmq: { condition: service_healthy }
       ports:
         - "${TRY_WARREN_PORT:-8080}:8080"
       environment:
         WARREN_RABBIT_ID: try
         WARREN_RABBIT_NAME: Try-out broker
         WARREN_RABBIT_MANAGEMENT_URL: http://rabbitmq:15672
         WARREN_RABBIT_HOST: rabbitmq
         WARREN_RABBIT_USERNAME: warren
         WARREN_RABBIT_PASSWORD: warren
         WARREN_ADMIN_USERNAME: admin
         WARREN_ADMIN_PASSWORD: admin
       volumes:
         - warren-data:/app/data
   
   volumes:
     warren-data:

2. 2
   docker compose -f docker-compose.try.yml up -dCopy
3. 3
   Open localhost:8080, sign in as admin / admin, open orders.dlq.

Done? docker compose -f docker-compose.try.yml down -v removes it all.

No Docker at hand? See what you would get: the recordings above, or the four-minute walkthrough on YouTube.

services:
  warren:
    image: ghcr.io/viba88/warren:0.17
    ports: ["8080:8080"]
    volumes: [warren-data:/app/data]
    environment:
      WARREN_RABBIT_MANAGEMENT_URL: http://rabbitmq:15672
      WARREN_RABBIT_HOST: rabbitmq
      WARREN_RABBIT_USERNAME: warren
      WARREN_RABBIT_PASSWORD: ${RABBIT_PASSWORD}
      WARREN_ADMIN_PASSWORD: ${WARREN_ADMIN_PASSWORD}
      # Team/Pro: WARREN_LICENSE_KEY
      # Pro: WARREN_DB_URL, WARREN_OIDC_ISSUER_URI
volumes:
  warren-data:

docker compose up -d, then sign in on port 8080 as admin with the password you set. The RabbitMQ user needs the management tag and read/write on the vhost; add monitoring to see disk and memory of the nodes. Full examples, also with PostgreSQL, are in the documentation.