Understanding HTTP Status Codes with Examples
Every time you visit a website, your browser sends a request to a server. That server responds with an HTTP status code. You may not always see them, but they're always there behind the scenes — helping your browser understand whether the request succeeded, failed, or needs more information.
If you’re building web apps, APIs, or working with servers, understanding HTTP status codes is essential. This guide breaks them down into categories and gives real examples to help you remember what each one means.
What Are HTTP Status Codes?
HTTP status codes are 3-digit numbers returned by a server in response to an HTTP request. They’re divided into five classes, each beginning with a different number:
| Category | Range | Meaning |
|---|---|---|
| 1xx | 100–199 | Informational |
| 2xx | 200–299 | Success |
| 3xx | 300–399 | Redirection |
| 4xx | 400–499 | Client Errors |
| 5xx | 500–599 | Server Errors |
1xx – Informational Responses
These are rare in frontend development and mostly used in protocol-level communication.
100 Continue
The server has received the request headers, and the client can proceed with the body. Used in complex requests like file uploads.
101 Switching Protocols
The server agrees to switch to a different protocol, like WebSocket.
2xx – Success Codes
These indicate that the request was received, understood, and accepted.
200 OK
The standard success response. This means the request worked exactly as expected.
GET /products → 200 OK201 Created
Used when a new resource has been successfully created.
POST /users → 201 Created204 No Content
The request succeeded, but there’s nothing to return. Often used when deleting a resource.
DELETE /comments/123 → 204 No Content3xx – Redirection Codes
These tell the client to make another request to a different location.
301 Moved Permanently
The resource has been moved to a new URL. Browsers will cache this redirect.
GET /old-page → 301 → /new-page302 Found
Temporarily redirected. The client should use the original URL again next time.
304 Not Modified
The client’s cached version is still valid. No need to download again.
GET /style.css → 304 Not Modified4xx – Client Error Codes
These mean something went wrong with the request from the user’s side.
400 Bad Request
The request was malformed, missing parameters, or had invalid syntax.
POST /users with missing "email" → 400 Bad Request401 Unauthorized
Authentication is required but missing or invalid.
GET /dashboard without token → 401 Unauthorized403 Forbidden
You’re authenticated but don’t have permission to access the resource.
GET /admin-panel as regular user → 403 Forbidden404 Not Found
The requested resource could not be found.
GET /products/9999 → 404 Not Found405 Method Not Allowed
The request method is not supported for the endpoint.
PUT /login → 405 Method Not Allowed429 Too Many Requests
You’ve hit a rate limit. The server is telling you to slow down.
5xx – Server Error Codes
These mean the server failed to handle a valid request.
500 Internal Server Error
Something went wrong on the server — usually a bug or crash.
GET /products → 500 Internal Server Error502 Bad Gateway
A server acting as a gateway or proxy received an invalid response from the upstream server.
503 Service Unavailable
The server is currently down for maintenance or overloaded.
504 Gateway Timeout
The upstream server took too long to respond.
How to See HTTP Status Codes
You can see status codes in several ways:
- Browser Dev Tools: Open the Network tab, reload the page, and inspect the status of each request.
- Postman: Run any request and look for the status code above the response.
- curl: Use the terminal to make a request and get the response code.
curl -I https://example.comThis returns only the response headers, including the status code.
Status Code Quick Reference
| Status | Meaning | Common Use |
|---|---|---|
| 200 | OK | Successful GET or POST |
| 201 | Created | New user, resource created |
| 204 | No Content | Delete action completed |
| 301 | Moved Permanently | Redirect old route to new one |
| 400 | Bad Request | Missing or invalid input |
| 401 | Unauthorized | Missing token or auth failure |
| 403 | Forbidden | Not allowed to access |
| 404 | Not Found | URL does not exist |
| 500 | Internal Server Error | Bug on the backend |
Once you get familiar with these codes, you'll find them incredibly helpful while debugging your apps, handling API responses, or setting up error messages for users.