Understanding API Endpoints
Table of Contents
What are API Endpoints?
An API endpoint is a specific URL where an API can be accessed by a client application. It represents a single entry point to a set of functionalities provided by the server. Think of each endpoint as a function call over HTTP.
URL Structure
Endpoints are built using a base URL combined with resource paths and optional query parameters.
https://api.example.com/v1/users/{id}?include=posts,comments
HTTP Methods
The method used conveys the type of operation.
- GET: Retrieve data.
- POST: Create a new resource.
- PUT: Replace an existing resource.
- PATCH: Partially update a resource.
- DELETE: Remove a resource.
Status Codes
Responses include a status code that indicates the result of the request.
| Code | Meaning |
|---|---|
| 200 | OK – Successful GET. |
| 201 | Created – Successful POST. |
| 400 | Bad Request – Invalid syntax. |
| 401 | Unauthorized – Authentication required. |
| 404 | Not Found – Resource does not exist. |
| 500 | Server Error – Something went wrong on the server. |
Example Requests
GET a user
curl -X GET "https://api.example.com/v1/users/42"
Create a new post
curl -X POST "https://api.example.com/v1/posts" \
-H "Content-Type: application/json" \
-d '{"title":"Hello World","body":"My first post"}'
Best Practices
- Version your API in the URL (
/v1/). - Use nouns for resources, not verbs.
- Leverage HTTP status codes consistently.
- Support filtering, pagination, and field selection via query parameters.
- Document every endpoint clearly with examples.