GraphQL

1. Introduction

   What GraphQL is, client-specified queries, single endpoint, strongly typed API, versus REST.

2. Schemas and types

   SDL, object types, scalars, enums, interfaces, unions, input types, non-null and lists.

3. Queries

   Fields, arguments, aliases, fragments, variables, directives, operation names.

4. Mutations

   Write operations, serial execution of mutation fields, input objects, returning updated data.

5. Subscriptions

   Real-time event streams, subscription operations, transport.

6. Validation

   Static validation of operations against the schema before execution.

7. Execution

   Resolvers, resolver chain, root fields, async resolution, default resolvers.

8. Response

   Response format: data, errors, extensions, partial results.

9. Introspection

   __schema and __type, querying a schema, tooling like GraphiQL.

10. Thinking in graphs

    Modeling data as a graph, nodes and edges, business-domain-oriented schema design.

11. Serving over HTTP

    GET and POST, JSON request bodies, status codes, content types.

12. Authorization

    Delegating authorization to the business logic layer, field-level access checks.

13. Pagination

    Cursor-based pagination, connections, edges, pageInfo, Relay specification.

14. Schema design

    Naming, nullability, evolving schema without versioning, deprecation.

15. Error handling

    Errors array, partial data, domain errors modeled in schema.

16. Global object identification

    Node interface, global unique IDs, refetching objects.

17. Caching

    HTTP caching limits, global unique IDs for client caches, persisted queries.

18. Performance

    N+1 problem, DataLoader batching, query cost, complexity limits.

19. Security

    Query depth and cost limiting, timeouts, disabling introspection, rate limiting.

20. Federation

    Composing multiple GraphQL services into one supergraph.

Each section links to the official page. Titles and summaries by Extra Credit; the docs belong to their authors.