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HTTP Error Code Explainer

Type a status code or browse categories to learn what each HTTP code means.

37 of 37 status codes

Category
  • 100

    Continue

    1xx

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

    Common Use Cases: Large file uploads where the client checks if the server is willing to accept the request.

  • 101

    Switching Protocols

    1xx

    The server agrees to switch protocols as requested by the client via the Upgrade header.

    Common Use Cases: Upgrading HTTP connections to WebSocket.

  • 102

    Processing

    1xx

    The server has received and is processing the request, but no response is available yet.

    Common Use Cases: Long-running WebDAV operations to prevent client timeouts.

  • 103

    Early Hints

    1xx

    Used to return some response headers before the final HTTP message.

    Common Use Cases: Preloading resources like CSS and fonts while the server prepares the main response.

  • 200

    OK

    2xx

    The request has succeeded. The meaning depends on the HTTP method used.

    Common Use Cases: Standard response for successful GET, PUT, or DELETE requests.

  • 201

    Created

    2xx

    The request has been fulfilled and resulted in a new resource being created.

    Common Use Cases: Successful POST requests that create a new resource (e.g., user registration).

  • 202

    Accepted

    2xx

    The request has been accepted for processing, but the processing has not been completed.

    Common Use Cases: Asynchronous operations like batch processing or queued tasks.

  • 204

    No Content

    2xx

    The server successfully processed the request and is not returning any content.

    Common Use Cases: Successful DELETE requests or PUT updates where no body is needed.

  • 206

    Partial Content

    2xx

    The server is delivering only part of the resource due to a Range header sent by the client.

    Common Use Cases: Video streaming, resumable file downloads, and pagination of large files.

  • 207

    Multi-Status

    2xx

    Conveys information about multiple resources where multiple status codes might be appropriate.

    Common Use Cases: WebDAV batch operations returning individual results for each sub-request.

  • 301

    Moved Permanently

    3xx

    The resource has been permanently moved to a new URI. Future requests should use the new URI.

    Common Use Cases: Domain migrations, URL restructuring, and enforcing canonical URLs.

  • 302

    Found

    3xx

    The resource resides temporarily under a different URI.

    Common Use Cases: Temporary redirects during maintenance or A/B testing.

  • 303

    See Other

    3xx

    The response to the request can be found under another URI using a GET method.

    Common Use Cases: Redirecting after a POST form submission (Post/Redirect/Get pattern).

  • 304

    Not Modified

    3xx

    The resource has not been modified since the version specified by the request headers.

    Common Use Cases: Browser caching — serves cached content when ETag or Last-Modified hasn't changed.

  • 307

    Temporary Redirect

    3xx

    The request should be repeated with another URI, but future requests should still use the original URI. Method and body are not changed.

    Common Use Cases: HTTPS enforcement or temporary URL changes while preserving the HTTP method.

  • 308

    Permanent Redirect

    3xx

    The resource has been permanently moved. Similar to 301, but the method and body must not be changed.

    Common Use Cases: Permanent URL changes where POST/PUT methods must be preserved.

  • 400

    Bad Request

    4xx

    The server cannot process the request due to a client error (malformed syntax, invalid parameters).

    Common Use Cases: Invalid JSON body, missing required fields, or malformed query parameters.

  • 401

    Unauthorized

    4xx

    Authentication is required and has failed or has not been provided.

    Common Use Cases: Missing or invalid authentication token, expired session.

  • 403

    Forbidden

    4xx

    The server understood the request but refuses to authorize it.

    Common Use Cases: Insufficient permissions, IP blocking, or accessing restricted resources.

  • 404

    Not Found

    4xx

    The server cannot find the requested resource.

    Common Use Cases: Invalid URL, deleted resource, or accessing a non-existent API endpoint.

  • 405

    Method Not Allowed

    4xx

    The request method is not supported for the requested resource.

    Common Use Cases: Sending POST to a read-only endpoint, or DELETE to a resource that doesn't support it.

  • 406

    Not Acceptable

    4xx

    The server cannot produce a response matching the list of acceptable values defined in the request headers.

    Common Use Cases: Content negotiation failure — the client requests a format the server cannot provide.

  • 408

    Request Timeout

    4xx

    The server timed out waiting for the request.

    Common Use Cases: Slow client connections, abandoned requests, or network issues.

  • 409

    Conflict

    4xx

    The request could not be completed due to a conflict with the current state of the resource.

    Common Use Cases: Concurrent editing conflicts, duplicate resource creation, or version mismatches.

  • 410

    Gone

    4xx

    The resource is no longer available and no forwarding address is known.

    Common Use Cases: Permanently deleted API endpoints or deprecated resources.

  • 413

    Content Too Large

    4xx

    The request entity is larger than limits defined by the server.

    Common Use Cases: File upload exceeding maximum size, oversized JSON payload.

  • 414

    URI Too Long

    4xx

    The URI provided was too long for the server to process.

    Common Use Cases: Extremely long query strings, often from passing too much data via GET parameters.

  • 415

    Unsupported Media Type

    4xx

    The media format of the requested data is not supported by the server.

    Common Use Cases: Sending XML to an endpoint expecting JSON, or wrong Content-Type header.

  • 418

    I'm a Teapot

    4xx

    The server refuses the attempt to brew coffee with a teapot (RFC 2324).

    Common Use Cases: Easter egg responses, API humor, or signaling intentional rejection.

  • 422

    Unprocessable Content

    4xx

    The server understands the content type but was unable to process the contained instructions.

    Common Use Cases: Validation errors — correct JSON format but invalid business logic (e.g., invalid email).

  • 429

    Too Many Requests

    4xx

    The user has sent too many requests in a given amount of time (rate limiting).

    Common Use Cases: API rate limiting, brute force protection, or DDoS mitigation.

  • 451

    Unavailable For Legal Reasons

    4xx

    The resource is unavailable due to legal demands (censorship, court order).

    Common Use Cases: Content blocked due to GDPR, DMCA takedowns, or government censorship.

  • 500

    Internal Server Error

    5xx

    The server encountered an unexpected condition that prevented it from fulfilling the request.

    Common Use Cases: Unhandled exceptions, configuration errors, or database failures.

  • 501

    Not Implemented

    5xx

    The server does not support the functionality required to fulfill the request.

    Common Use Cases: API endpoints under development or unsupported HTTP methods.

  • 502

    Bad Gateway

    5xx

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

    Common Use Cases: Reverse proxy issues, upstream server crashes, or load balancer misconfigurations.

  • 503

    Service Unavailable

    5xx

    The server is not ready to handle the request, often due to maintenance or overload.

    Common Use Cases: Planned maintenance, server overload, or dependency failures.

  • 504

    Gateway Timeout

    5xx

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

    Common Use Cases: Slow upstream services, network latency, or long-running backend operations.