When is it best to use gRPC for communication between microservices?

gRPC is better suited for interaction between microservices when high performance, low latency, and strict data typing are important. It is well suited if:

• Bidirectional streaming of data is required.
• Strict contract definitions via Protocol Buffers are needed.
• Services are written in different languages, and cross-platform compatibility is necessary.
• Message compactness and efficient network usage are important.

For example, if microservices exchange a large number of requests in real-time or operate under bandwidth constraints, gRPC would be preferable over REST API on HTTP/JSON.