Message Queues: The Simple Explanation

Dev Oza — Sun, 06 Sep 2026 14:44:27 +0000

Why Do We Need Message Queues?

When building a backend application, it's tempting to do everything inside a single API request.

For example, when a user uploads a video:

The problem?

The user has to wait for all of these operations to finish.

Instead, we can move the slow or non-critical work to a queue.

The API can simply:

A background worker can then process the message.

For example:

User → API → Queue → Worker
                 ↓
             Processing

Popular choices include Kafka, RabbitMQ, and Amazon SQS.

The user doesn't need to wait for background tasks.

We can run multiple workers when the workload increases.

If a worker crashes, the message can remain in the queue and be processed later.

The API doesn't need to know how every background task is implemented.

Message queues also introduce complexity.

Now we need to think about:

So, should you always use a message queue?

No.

If your operation is simple and fast, a queue may just add unnecessary complexity.

Use it when you have background work, high traffic, or a need to decouple services.

Good system design isn't about adding more components. It's about adding the right component when you actually have a problem to solve.