Deprecation
BackendAnnouncing that something will be removed.
Marking a field or endpoint as going away while still supporting it, so callers have time to move. Only meaningful if you can measure who is still using it.
See also Breaking change, Versioning
Endpoint
BackendOne address on a server that does one thing.
A path and a method together. The same path with a different verb is a different endpoint doing something different: GET /orders lists them, POST /orders creates one.
See also API, HTTP, Idempotency
GraphQL
BackendAn API style where the client states what it wants.
One endpoint that accepts a description of the desired data. Fills a rich screen in one round trip with no unused fields, at the cost of much harder caching and rate limiting.
See also REST, RPC, API
REST
BackendAn API style organised around things.
Endpoints named after resources (/users, /orders) with HTTP verbs saying what to do to them. Highly cacheable and easy to inspect. A rich screen may need several calls.
See also GraphQL, RPC, Endpoint