Message Queue Simulator — Interactive System Design Lab

Produce messages and watch multiple consumers process them in parallel. Toggle between at-least-once and at-most-once delivery modes, observe how ordering guarantees hold or break under load, and understand how queues decouple services so producers and consumers can fail independently.

Drop messages into a queue, watch consumers race to process them, and break delivery guarantees to see why idempotency matters.

This free interactive simulation runs directly in your browser — no account needed. Adjust the parameters and watch how the system responds in real time.

Concepts covered

• message queue
• producer consumer
• Kafka
• RabbitMQ
• at-least-once
• exactly-once
• async messaging

Read the guide

• Message Queues — The secret to calming down a chaotic system. Learn how to decouple your services, smooth out traffic spikes, and choose between the two giants: RabbitMQ and Kafka.