# MQ
Why MQ Came in Place
AWS MQ is a managed message broker service.\
A message broker is like a post office for computers: it helps different applications or services send messages to each other reliably.
Think of it like this:
* App A wants to tell App B: “Order placed.”
* AWS MQ ensures that message gets delivered safely and in order, even if App B is busy or temporarily offline.
Why use AWS MQ?
* Managed Service: AWS handles setup, maintenance, scaling, and patches. You don’t have to manage servers.
* Reliable Messaging: Guarantees messages are delivered once and in order.
* Compatibility: Supports standard messaging protocols like ActiveMQ and RabbitMQ, so apps don’t need major changes.
* Decoupling: Apps don’t communicate directly. They send messages to MQ, which delivers them—making systems more stable.
#### **Simple Example**
* Online Store:
* Customer places order → message sent to MQ → inventory service receives message → updates stock → shipping service receives same message → ships order.
* Even if inventory or shipping is temporarily down, MQ keeps the message safe until the service is ready.
SNS architecture
SQS architecture
MQ architecture
Default you should use SNS SQS
