Networking & Web

HTTP Status Code Reference

Look up any HTTP status code and see its meaning, grouped and color-coded by informational, success, redirect, client error, and server error.

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Showing 28 of 28 codes

100

Continue

The server has received the request headers and the client should proceed to send the request body.

101

Switching Protocols

The requester has asked the server to switch protocols and the server has agreed to do so (e.g., HTTP → WebSocket).

200

Standard response for successful HTTP requests. The actual response depends on the request method used.

201

Created

The request has been fulfilled, resulting in the creation of a new resource. Returned after successful POST requests.

202

Accepted

The request has been accepted for processing, but the processing has not been completed (async operations).

204

No Content

The server successfully processed the request and is not returning any content. Common for DELETE requests.

206

Partial Content

The server is delivering only part of the resource due to a Range header sent by the client (used for resumable downloads).

301

Moved Permanently

This and all future requests should be directed to the given URI. Used for permanent URL redirects (SEO-friendly).

302

Found

The URI requested has been temporarily moved. The client should follow the redirect but keep using the original URI for future requests.

304

Not Modified

Resource has not been modified since the version specified by request headers. Client should use its cached version.

307

Temporary Redirect

Request should be repeated with another URI but future requests should still use the original URI. Preserves the HTTP method.

308

Permanent Redirect

Permanent redirect that preserves the original HTTP method (unlike 301 which may change POST to GET).

400

Bad Request

The server cannot or will not process the request due to an apparent client error (malformed syntax, invalid request message framing).

401

Unauthorized

Authentication is required and has failed or has not yet been provided. The user must provide credentials.

403

Forbidden

The server understood the request but refuses to authorize it. Unlike 401, re-authenticating will make no difference.

404

Not Found

The requested resource could not be found but may be available in the future. No indication of whether the condition is permanent or temporary.

405

Method Not Allowed

A request method is not supported for the requested resource. The response must include an Allow header with supported methods.

408

Request Timeout

The server timed out waiting for the request. The client may repeat the request without modifications.

409

Conflict

Indicates that the request could not be processed because of a conflict in the current state of the resource (e.g., optimistic locking failure).

410

Gone

The resource requested is no longer available and will not be available again. Unlike 404, it is a permanent condition.

413

Payload Too Large

The request is larger than the server is willing or able to process (file upload size limit exceeded).

422

Unprocessable Entity

The request was well-formed but was unable to be followed due to semantic errors. Common in REST APIs for validation failures.

429

Too Many Requests

The user has sent too many requests in a given amount of time. Used for rate limiting. Response should include Retry-After header.

500

Internal Server Error

A generic error message when an unexpected condition was encountered and no more specific message is suitable.

501

Not Implemented

The server either does not recognize the request method, or it lacks the ability to fulfil the request.

502

Bad Gateway

The server was acting as a gateway or proxy and received an invalid response from the upstream server.

503

Service Unavailable

The server cannot handle the request (overloaded or down for maintenance). Should include Retry-After header.

504

Gateway Timeout

The server was acting as a gateway or proxy and did not receive a timely response from the upstream server.

HTTP Status Codes Reference

HTTP status codes are three-digit integers that servers include in every response to indicate the outcome of the request. They are grouped into five classes based on the first digit.

2xx Success

200 OK is the default success response. 201 Created confirms a successful POST that created a resource. 204 No Content is ideal for DELETE operations. 206 Partial Content powers resumable file downloads and video streaming (e.g., Netflix seeking through a video).

3xx Redirection and SEO

301 Moved Permanently transfers link equity (PageRank) to the new URL, making it the correct choice for permanent URL changes in SEO. 302 Found for temporary redirects retains link equity at the original URL. 307 and 308 are method-safe versions that guarantee the POST body is re-sent to the new URL.

4xx Client Errors

401 Unauthorized means credentials are needed. 403 Forbidden means credentials were provided but are insufficient. 404 Not Found is cacheable; 410 Gone is more definitive and helps search engines remove indexed pages faster. 429 Too Many Requests enables API rate limiting.

5xx Server Errors

500 Internal Server Error indicates an unhandled exception — always log these with stack traces. 503 Service Unavailable with a Retry-After header tells clients and load balancers when to retry. 502 Bad Gateway often indicates a crashed upstream service or a misconfigured reverse proxy (Nginx, Caddy).

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Type "404" or "not found" and get an instant match.

Read the explanation

Each code includes a plain-language description of when it applies.

Scan by category

1xx, 2xx, 3xx, 4xx, and 5xx are color-coded for quick visual grouping.

Common questions

Frequently asked questions

What is the difference between 401 and 403?

401 means authentication is missing or invalid, while 403 means the server recognized the request but is refusing it regardless of credentials.

Does it cover less common codes like 418?

Yes, both the everyday codes and the more obscure or rarely used ones are included.

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Networking & Web

HTTP status codes are three-digit integers that servers include in every response to indicate the outcome of the request. They are grouped into five classes based on the first digit.

HTTP Status Code Reference

HTTP Status Codes Reference

2xx Success

3xx Redirection and SEO

4xx Client Errors

5xx Server Errors

Three steps, no setup

Search by code or name

Read the explanation

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Frequently asked questions

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HTTP Status Codes Reference

2xx Success

3xx Redirection and SEO

4xx Client Errors

5xx Server Errors