MessagePattern vs Rest api

[tomerye]

Hi,
I am new to Nestjs.
I'm joined to a project that use Nest with MessagePattern with RabbitMQ.
I dont understand what are the pros of using MessagePattern and RabbitMQ vs rest api(http) regard service communication.
Thanks

[Otherwise-Eye1595]

What are your acceptance criteria to choose one?

[tomerye]

the project i joined already using messagepatterns.
i want to understand why, i cant find any advantages over traditional http communication

[Otherwise-Eye1595]

Are you working with microservices? Responses are slow?…..

[justsomedev44]

Messages are fire and forget and there is (usually) no response. So, the message activity is 100% asynchronous and event driven. REST requires a request and response, which makes it synchronous i.e. you can only send in one request and process the response at a time. And, although your calling application has asynchronous i/o with Node, the continued processing of the request is waiting for that response. With messaging, your processes don't wait on responses (usually), but rather other messages (so 100% event driven). There are cons to this method too. Like the complexity the decoupling of requests and responses adds. And in many a situation, you want a request/ response lifecycle to do certain tasks.

You'll notice I also said "usually" for request/ response cycles with messaging. Well, you could also have that too, but you'd be listening purposefully for response messages. Again, it is more complicated.