Rest? gRPC? GraphQL?

• Use REST if:
  1. You’re building a CRUD-style web application.
  2. Your API is mostly manipulating well-structured related data.
  3. Your API needs to be highly cacheable, including support for intermediate proxy caching.
• Use gRPC if:
  1. Your API is private and powers communications between parts of a microservices architecture.
  2. Your API is mostly about actions.
  3. You need to collect data from IoT devices.
  4. You’re implementing a Backend For Frontend pattern for a mobile application with stable API request patterns.
  5. Performance is a critical requirement.
• Use GraphQL if:
  1. You’re building a public API and you want it to be highly flexible in terms of customizing requests.
  2. You want to defer defining your API surface until you have a chance to analyze which resources your clients tend to request.
  3. You want to aggregate internal data from multiple sources into a public API for multiple clients with varying data requirements.

https://speedscale.com/choosing-an-api-technology-grpc-rest-graphql/