go-graphql

# Go GraphQL Both production-grade Go GraphQL libraries are schema-first: write SDL (`.graphql`), bind Go resolvers. Pick the library, write the schema deliberately, and treat DataLoaders + complexity limits as non-optional. ## Core Rules 1. **Schema is the contract.** Design nullability and pagination once; clients depend on it forever. A change from nullable to non-null is a breaking change. 2. **Resolvers are thin.** Translate GraphQL input → domain call → GraphQL output. No SQL, no business logic. 3. **DataLoaders are per-request.** Construct in HTTP middleware, stash in `context`. A package-level DataLoader is a cross-tenant data leak. 4. **Authenticate in middleware, authorize in the schema.** HTTP middleware extracts identity; schema directives (or resolver checks) enforce per-field rules. 5. **Subscriptions respect context.** Every subscription goroutine selects on `ctx.Done()` and `defer close(ch)`. Otherwise a disconnected client leaks a goroutine forever. 6. **Production limits are non-optional.** Set complexity caps; gate introspection by environment; never expose raw internal errors. ## Library Decision | Library | Approach | Type safety | Build step | Pick when | |---|---|---|---|---| | `github.com/99designs/gqlgen` | Codegen | Compile-time | `go generate` | Large schemas, Federation, strict types | | `github.com/graph-gophers/graphql-go` | Reflection | Parse-time | None | Small/medium schemas, simple pipeline | | `github.com/graphql-go/graphql` | Code-firs...