Software Architect's Handbook

Client-side discovery pattern

With the client-side discovery pattern, the service client, whether it is an API gateway or another service, queries a service registry for the locations of available service instances:

Once the locations of available service instances are obtained from the service registry, the service client uses a load balancing algorithm to select one of them. At that point, the service client can interact with a specific service instance.

This pattern is straightforward, although it does couple the service client with the service registry. For organizations that are taking advantage of using multiple programming languages ...