Rest

REST (Representational State Transfer) is a HTTP-based web service for communication between applications.

REST, or REpresentational State Transfer, is an architectural style for providing standards between apps and systems, making it easier for systems to communicate with each other (even, and especially, if they are decoupled microservices!). REST-compliant systems, often called RESTful systems.

https://searchmicroservices.techtarget.com/definition/REST-representational-state-transfer

REST is alternative to SOAP

The two competing styles for implementing web services are REST and SOAP. The fundamental difference between the two is the philosophical approach the two have to remotely invocations.

REST takes a resource-based approach to web-based interactions. With REST, you locate a resource on the server, and you choose to either update that resource, delete it or get some information about it.

With SOAP, the client doesn't choose to interact directly with a resource, but instead calls a service, and that service mitigates access to the various objects and resources behind the scenes.

Systems that follow the REST paradigm are stateless, meaning that the server does not need to know anything about what state the client is in and vice versa. In this way, both the server and the client can understand any message received, even without seeing previous messages. This constraint of statelessness is enforced through the use of  resources, rather than  commands. Resources are the nouns of the Web - they describe any object, document, or  thing  that you may need to store or send to other services.