Common HTTP Status Codes Explained

HTTP status codes are three-digit server responses that show whether a request succeeded, was redirected, contained a client-side problem, or met a server-side failure. Codes beginning with 2 mean success, 3 mean redirection, 4 mean a client error, and 5 mean a server error.

What do HTTP status codes mean?

An HTTP status code is part of the response a server sends after a browser, app, or other client requests a resource. The code describes the result of that particular request; it does not always describe the condition of the entire website.

• 1xx informational: The request is still being processed or the connection is changing state.
• 2xx successful: The server received and handled the request successfully.
• 3xx redirection: The client must use another location or may reuse a cached copy.
• 4xx client error: The server could not fulfill the request because of the request, credentials, permissions, rate limit, or requested resource.
• 5xx server error: The server failed while handling an apparently valid request.

These classes make common website status codes easier to identify, but the complete three-digit code provides the specific meaning.

What are the common 2xx status codes?

Common 2xx status codes confirm that the request succeeded, although a successful response does not always contain visible content.

• 200 OK: The request succeeded. The response normally contains the requested representation or the result of the action.
• 201 Created: The request succeeded and created one or more resources. An application programming interface, or API, may return this after accepting a creation request.
• 204 No Content: The server successfully completed the request but has no response content to send. A blank response is therefore expected.

What are the common 3xx status codes?

Common 3xx status codes tell a client that another step or a cached response is involved. Some redirects preserve the original request method, while others may be treated differently by clients.

• 301 Moved Permanently: The resource has a new permanent location. Clients and search systems may update stored references.
• 302 Found: The resource is temporarily available at another location. The original address remains relevant for later requests.
• 304 Not Modified: A conditional request shows that the stored version is still current. The client can reuse its cached copy; this is not a normal redirect to a different page.
• 307 Temporary Redirect: The temporary redirect preserves the original HTTP request method and request content.
• 308 Permanent Redirect: The permanent redirect preserves the original HTTP request method and request content.

The key distinction among these common 3xx status codes is whether the move is permanent or temporary, whether the method must remain unchanged, or whether cached content can be reused.

What are the common 4xx status codes?

Common 4xx status codes mean the server found a problem associated with the request. Calling them client errors does not prove that the visitor personally caused the problem; a broken link, expired credentials, or site configuration can produce one.

• 400 Bad Request: The server cannot process the request because it appears malformed or invalid.
• 401 Unauthorized: Authentication credentials are missing, invalid, or insufficient for authentication. Despite the name, this code concerns authentication.
• 403 Forbidden: The server understood the request but refuses to fulfill it, commonly because access is not permitted.
• 404 Not Found: The server cannot find the requested resource or is not disclosing whether it exists.
• 405 Method Not Allowed: The resource exists, but it does not support the HTTP method used for this request.
• 408 Request Timeout: The server did not receive a complete request within the time it was prepared to wait.
• 409 Conflict: The request conflicts with the resource's current state, such as an incompatible update.
• 410 Gone: The resource is no longer available and the condition is expected to be permanent.
• 413 Content Too Large: The request content exceeds a limit the server is willing or able to process.
• 415 Unsupported Media Type: The request uses a content format the server does not support for that request.
• 422 Unprocessable Content: The server understands the content type and syntax but cannot process the contained instructions.
• 429 Too Many Requests: The client sent more requests than the server permits within a period. The response may indicate how long to wait.

What are the common 5xx status codes?

Common 5xx status codes indicate that a server failed to fulfill an apparently valid request. The failure may occur on the website's server or on an upstream system it depends on.

• 500 Internal Server Error: The server encountered an unexpected condition without providing a more specific applicable code.
• 501 Not Implemented: The server does not support the functionality needed to fulfill the request.
• 502 Bad Gateway: A server acting as a gateway or proxy received an invalid response from an upstream server.
• 503 Service Unavailable: The server is temporarily unable to handle the request, often because of overload or maintenance.
• 504 Gateway Timeout: A gateway or proxy did not receive a timely response from an upstream server.

How should you respond to an HTTP error?

The right response to common HTTP error codes depends on whether you are visiting the page or operating the service. Not every error can be fixed on the device that displays it.

1. If you are a visitor: Check the address for typing errors, reload once, and return to the site's main navigation if a deep page returns 404 or 410. For 429, 500, 502, 503, or 504, pause before trying again so repeated requests do not add load.
2. If access is restricted: For 401 or 403, confirm that you are using the intended account and that the account has permission. Repeated attempts will not grant access that the server has denied.
3. If you own the site: Reproduce the request, record the exact code and time, then inspect application, proxy, and upstream service logs. Check redirects, permissions, routes, request limits, and recent configuration changes.
4. If you are developing a client: Read the response headers and content, preserve request methods where 307 or 308 requires it, and handle retries carefully. Do not retry every 4xx response automatically; many require a corrected request or authorization.

Together, these are the most common HTTP status codes encountered in browsers and APIs. The response body and headers can provide more context than the code alone.