MEPX
Chapter 2 of 10All chapters
  1. 1What an API is
  2. 2The request
  3. 3The response
  4. 4REST and its alternatives
  5. 5Authentication
  6. 6JSON and data shapes
  7. 7Pagination and filtering
  8. 8Rate limits and retries
  9. 9Versioning and change
  10. 10Calling and debugging APIs

Chapter 2 of 10

The request

Method, path, headers, body.

The four parts

The method says what kind of action, the path says which resource, headers carry metadata such as content type and authentication, and the body carries the data being sent.

  • GET reads, POST creates, PUT replaces, PATCH updates part, DELETE removes.
  • Query parameters filter and paginate; they are not the place for secrets.

Safe and idempotent

GET should change nothing, so caches and crawlers can repeat it freely. PUT and DELETE are idempotent: doing them twice leaves the same state, which makes retries safe.