Well-defined API design is very important in a microservices architecture, communication happens API calls.

▪ Designed APIs should be efficient and not to be chatty communications. APIs must have well-defined

documented and versioning.

▪ There are 2 type APIs sync communication in microservices:

▪ Public APIs: API calls from the client apps.

▪ Backend APIs: inter-service communication between backend services.

▪ Public APIs

Use RESTful APIs over HTTP protocol. RESTful APIs use

JSON payloads for request-response, that easy to check

payloads and easy agreement with clients.

▪ Backend APIs

Inter-service communication can result in a lot of network

traffic. serialization speed and payload size become more

important. Using gRPC is mandatory for increase network

performance

https://medium.com/the-software-design-blog/an-introduction-to-rest-apis-and-microservices-ea9477699b73