What is the difference between message broker and message queue?

Question

Accepted Answer

**Message Broker** — intermediary for messaging. **Message Queue** — specific pattern.

**Message Broker:**
- Intermediary between services.
- Supports multiple patterns.
- Routing, transformation.
- RabbitMQ, Kafka, ActiveMQ.

```
Message Broker:
Producer → [Broker] → Consumer 1
                    → Consumer 2
  (Routing, transformation, multiple patterns)
```

**Message Queue:**
- Specific pattern within broker.
- FIFO ordering.
- One consumer per message.
- Work distribution.

```
Message Queue:
Producer → [Queue] → Consumer
  (FIFO, one consumer per message)
```

**Relationship:**
- Message Queue is one pattern.
- Message Broker supports multiple patterns.
- Pub/Sub is another pattern.

**Key differences:**
- **Broker** — infrastructure.
- **Queue** — pattern.
- **Broker** — supports many patterns.
- **Queue** — one specific pattern.

Systems Analyst: What is the difference between message broker and message queue?