CRUD, REST, and HTTP Verbs¶

CRUD describes operations on data. REST describes how to expose those operations over HTTP. They map almost one-to-one.

The Mapping¶

Resource-Oriented URLs¶

REST treats data as resources addressed by nouns, not verbs:

✅ GET /tasks ✅ POST /tasks ✅ DELETE /tasks/42 ❌ GET /getTasks ❌ POST /createTask ❌ GET /deleteTask?id=42

The HTTP method is the verb. The URL is the noun. Don't put verbs in the path.

Safe vs. Idempotent¶

Two properties matter when designing CRUD endpoints:

• Safe — the request does not change server state. GET is safe.
• Idempotent — calling it many times has the same effect as calling it once. GET, PUT, and DELETE are idempotent; POST is not.

POST /tasks (twice) → creates TWO tasks (not idempotent) PUT /tasks/42 (twice) → same final state (idempotent) DELETE /tasks/42 (twice) → gone after first call (idempotent)

Designing with these properties in mind makes retries, caching, and offline sync far safer.

PUT vs PATCH¶

• PUT replaces the entire resource. Omitted fields are reset.
• PATCH updates only the fields you send.

We'll dig into the difference — and when each matters — in Chapter 6.