One-to-one communication microservice patterns

At an individual microservice level, the data management pattern is composed of a suite of small services, with its own local data store, communicating with a REST API or via publish/subscribe:

API Gateway is a single entry point for all clients, and tailored for them, allowing changes to be decoupled from the main microservice API, which is especially useful for external-facing services.

One-to-one request/response can be sync or async. If they are sync, they can have a response for each request. If the communication is async, they can have an async response or async notification. Async is generally preferred and much more scalable, as it does not hold an open connection (non-blocking), and makes better use of the central processing unit (CPU) and input/output (I/O) operations.

We will go into further detail on the data-management patterns later in the book, where we will be looking at how microservices integrate in a wider ecosystem.