GraphQL shifts the design work from endpoint definition to schema design. The schema is the API — every type, field, query, and mutation is declared in the schema, and the schema governs everything the API can do. Designing a GraphQL schema well requires understanding how types compose, how to express mutations that reflect real domain operations, and where GraphQL’s conventions differ meaningfully from REST patterns that GraphQL developers often import by habit.

Every API starts with a choice that will shape every decision that follows: what protocol are you building on? REST, GraphQL, and gRPC are the three dominant options in modern API development, and none of them is universally correct. Each reflects a different set of assumptions about who is calling the API, how often, and what they need back.

Understanding the tradeoffs is not optional knowledge for serious API developers. It is the foundation.