Mapping HTTP Methods to CRUD Operations

The CRUD-to-HTTP Mapping

REST APIs conventionally map database CRUD (Create, Read, Update, Delete) operations to HTTP methods:

Standard Mapping

CRUD Operation	HTTP Method	Endpoint Pattern	Example
Create	POST	POST /resources	POST /api/users
Read (list)	GET	GET /resources	GET /api/users
Read (single)	GET	GET /resources/:id	GET /api/users/42
Update (full)	PUT	PUT /resources/:id	PUT /api/users/42
Update (partial)	PATCH	PATCH /resources/:id	PATCH /api/users/42
Delete	DELETE	DELETE /resources/:id	DELETE /api/users/42

URI Design

Resources are nouns, not verbs:

# Good
POST /api/users          (create a user)
GET  /api/users/42       (get user 42)
PUT  /api/users/42       (update user 42)

# Bad
POST /api/createUser
GET  /api/getUser?id=42
POST /api/updateUser

Nested Resources

GET    /api/users/42/posts         (list user 42's posts)
POST   /api/users/42/posts         (create a post for user 42)
GET    /api/users/42/posts/7       (get post 7 of user 42)
DELETE /api/users/42/posts/7       (delete post 7)

Status Code Conventions

Operation	Success Status	Common Errors
POST (create)	201 Created	400, 409, 422
GET (read)	200 OK	404
PUT (replace)	200 or 204	400, 404, 409
PATCH (update)	200 or 204	400, 404, 422
DELETE (remove)	204 No Content	404

Beyond Basic CRUD

Some operations do not fit neatly into CRUD:

• Search — GET /api/users/search?q=alice or POST /api/users/search for complex queries
• Bulk operations — POST /api/users/bulk-delete with a body of IDs
• Actions — POST /api/orders/42/cancel for non-CRUD actions