HTTP status codes are three-digit responses sent by a web server to indicate the outcome of a client’s request to the server. These codes help the client understand whether a request was successful, whether there was an error, or if further action is needed.
| Status Code | Category | Description |
| 1XX | Informational | Informational responses indicate that the request was received and understood, and further action is needed by the client. |
| 100 | Informational | Continue: The client should continue with its request. |
| 101 | Informational | Switching Protocols: The server is switching protocols as requested by the client. |
| 102 | Informational | Processing: The server has received and is processing the request, but no response is available yet. |
| 103 | Informational | Early Hints: Provides preliminary responses to the client before the final response is ready. |
| 2XX | Success | Success codes indicate that the client’s request was successfully received, understood, and accepted. |
| 200 | Success | OK: The request was successful, and the server returned the requested resource. |
| 201 | Success | Created: A new resource was successfully created. |
| 202 | Success | Accepted: The request has been accepted for processing but is not yet completed. |
| 203 | Success | Non-Authoritative Information: The request was successful, but the information may come from a different source. |
| 204 | Success | No Content: The request was successful, but there is no content to return. |
| 205 | Success | Reset Content: The client should reset the view or form that sent the request. |
| 206 | Success | Partial Content: The server is delivering only part of the resource due to a range header sent by the client. |
| 207 | Success | Multi-Status: The response contains multiple status codes, used for WebDAV. |
| 208 | Success | Already Reported: The members of a DAV binding have already been enumerated in a previous reply. |
| 226 | Success | IM Used: The server fulfilled a GET request for the resource, and the response is a result of instance-manipulations applied to the current instance. |
| 3XX | Redirection | Redirection codes indicate that further action needs to be taken by the client to complete the request. |
| 300 | Redirection | Multiple Choices: The request has more than one possible response. The user-agent or user should choose one of them. |
| 301 | Redirection | Moved Permanently: The resource has been permanently moved to a new URL. |
| 302 | Redirection | Found: The resource is temporarily available at a different URL. |
| 303 | Redirection | See Other: The client should retrieve the resource from another URI using a GET request. |
| 304 | Redirection | Not Modified: The resource has not been modified since the last request, so the client can use the cached version. |
| 307 | Redirection | Temporary Redirect: The resource is temporarily available at a different URI, and the request method should not change. |
| 308 | Redirection | Permanent Redirect: The resource has been permanently moved to a new URI, and the request method should not change. |
| 4XX | Client Error | Client error codes indicate that the client seems to have made an error in the request. |
| 400 | Client Error | Bad Request: The server cannot process the request due to a client error (e.g., malformed syntax). |
| 401 | Client Error | Unauthorized: Authentication is required to access the resource. |
| 402 | Client Error | Payment Required: Reserved for future use. |
| 403 | Client Error | Forbidden: The server understood the request but refuses to authorize it. |
| 404 | Client Error | Not Found: The requested resource could not be found on the server. |
| 405 | Client Error | Method Not Allowed: The request method is not supported for the requested resource. |
| 406 | Client Error | Not Acceptable: The requested resource is capable of generating only content not acceptable according to the Accept headers sent in the request. |
| 407 | Client Error | Proxy Authentication Required: The client must first authenticate itself with the proxy. |
| 408 | Client Error | Request Timeout: The server timed out waiting for the request. |
| 409 | Client Error | Conflict: The request could not be completed due to a conflict with the current state of the resource. |
| 410 | Client Error | Gone: The resource requested is no longer available and will not be available again. |
| 411 | Client Error | Length Required: The request did not specify the length of its content, which is required by the requested resource. |
| 412 | Client Error | Precondition Failed: The server does not meet one of the preconditions that the requester put on the request. |
| 413 | Client Error | Content Too Large: The request is larger than the server is willing or able to process. |
| 414 | Client Error | URI Too Long: The URI provided was too long for the server to process. |
| 415 | Client Error | Unsupported Media Type: The media format of the requested data is not supported by the server. |
| 416 | Client Error | Range Not Satisfiable: The range specified by the Range header field in the request cannot be fulfilled. |
| 417 | Client Error | Expectation Failed: The server cannot meet the requirements of the Expect request-header field. |
| 421 | Client Error | Misdirected Request: The request was directed at a server that is not able to produce a response. |
| 422 | Client Error | Unprocessable Content: The server understands the content type of the request entity, but was unable to process the contained instructions. |
| 423 | Client Error | Locked: The resource that is being accessed is locked. |
| 424 | Client Error | Failed Dependency: The request failed due to failure of a previous request. |
| 425 | Client Error | Too Early: Indicates that the server is unwilling to risk processing a request that might be replayed. |
| 426 | Client Error | Upgrade Required: The server refuses to perform the request using the current protocol but might be willing to do so after the client upgrades to a different protocol. |
| 428 | Client Error | Precondition Required: The origin server requires the request to be conditional. |
| 429 | Client Error | Too Many Requests: The user has sent too many requests in a given amount of time. |
| 431 | Client Error | Request Header Fields Too Large: The server is unwilling to process the request because its header fields are too large. |
| 451 | Client Error | Unavailable for Legal Reasons: The resource is unavailable due to a legal demand to deny access to it. |
| 5XX | Server Error | Server error codes indicate that the server failed to fulfill a valid request. |
| 500 | Server Error | Internal Server Error: The server encountered an unexpected condition, such as a misconfigured application or script error, that prevented it from fulfilling the request. |
| 501 | Server Error | Not Implemented: The server does not support the functionality required to fulfill the request, often due to a missing module or unsupported method. |
| 502 | Server Error | Bad Gateway: The server, while acting as a gateway or proxy, received an invalid response from an upstream server, often due to a reverse proxy or gateway issue. |
| 503 | Server Error | Service Unavailable: The server is temporarily unable to handle the request due to temporary overloading or maintenance of the server. |
| 504 | Server Error | Gateway Timeout: The server, acting as a gateway or proxy, did not receive a timely response from an upstream server or some other auxiliary server (e.g., DNS) it needed to access in order to complete the request. |
| 505 | Server Error | HTTP Version Not Supported: The server does not support the HTTP protocol version used in the request. |
| 506 | Server Error | Variant Also Negotiates: The server has an internal configuration error: the chosen variant resource is configured to engage in content negotiation itself, and is therefore not a proper endpoint in the negotiation process. |
| 507 | Server Error | Insufficient Storage: The server is unable to store the representation needed to complete the request, often due to a lack of disk space. |
| 508 | Server Error | Loop Detected: The server detected an infinite loop while processing a request with a resource, often due to circular references. |
| 511 | Server Error | Network Authentication Required: The client needs to authenticate to gain network access, often required by captive portals. |