◆Error Codes Wiki

HTTP Status Codes

Web server response codes including 1xx-5xx status codes. 211 items found.

Most Popular in HTTP Status Codes

http-200-okInformational

HTTP 200 OK — What It Means & How to Fix It

http-301-moved-permanentlyWarning

HTTP 301 Moved Permanently — What It Means & How to Fix It

http-302-foundWarning

HTTP 302 Found — What It Means & How to Fix It

http-400-bad-requestError

HTTP 400 Bad Request — What It Means & How to Fix It

http-401-unauthorizedError

HTTP 401 Unauthorized — What It Means & How to Fix It

http-403-forbiddenError

HTTP 403 Forbidden — What It Means & How to Fix It

All HTTP Status Codes Items

http-100-continueInformational

HTTP 100 Continue — What It Means & How to Fix It

http-101-switching-protocolsInformational

HTTP 101 Switching Protocols — What It Means & How to Fix It

http-102-processingInformational

HTTP 102 Processing — What It Means & How to Fix It

http-103-early-hintsInformational

HTTP 103 Early Hints — What It Means & How to Fix It

http-200-okInformational

HTTP 200 OK — What It Means & How to Fix It

http-201-createdInformational

HTTP 201 Created — What It Means & How to Fix It

http-202-acceptedInformational

HTTP 202 Accepted — What It Means & How to Fix It

http-203-non-authoritative-informationInformational

HTTP 203 Non-Authoritative Information — What It Means & How to Fix It

http-204-no-contentInformational

HTTP 204 No Content — What It Means & How to Fix It

http-205-reset-contentInformational

HTTP 205 Reset Content — What It Means & How to Fix It

http-206-partial-contentInformational

HTTP 206 Partial Content — What It Means & How to Fix It

http-207-multi-statusInformational

HTTP 207 Multi-Status — What It Means & How to Fix It

http-300-multiple-choicesWarning

HTTP 300 Multiple Choices — What It Means & How to Fix It

http-301-moved-permanentlyWarning

HTTP 301 Moved Permanently — What It Means & How to Fix It

http-302-foundWarning

HTTP 302 Found — What It Means & How to Fix It

http-303-see-otherWarning

HTTP 303 See Other — What It Means & How to Fix It

http-304-not-modifiedWarning

HTTP 304 Not Modified — What It Means & How to Fix It

http-305-use-proxyWarning

HTTP 305 Use Proxy — What It Means & How to Fix It

http-307-temporary-redirectWarning

HTTP 307 Temporary Redirect — What It Means & How to Fix It

http-308-permanent-redirectWarning

HTTP 308 Permanent Redirect — What It Means & How to Fix It

http-400-bad-requestError

HTTP 400 Bad Request — What It Means & How to Fix It

http-401-unauthorizedError

HTTP 401 Unauthorized — What It Means & How to Fix It

http-402-payment-requiredError

HTTP 402 Payment Required — What It Means & How to Fix It

http-403-forbiddenError

HTTP 403 Forbidden — What It Means & How to Fix It

http-404-not-foundError

HTTP 404 Not Found — What It Means & How to Fix It

http-405-method-not-allowedError

HTTP 405 Method Not Allowed — What It Means & How to Fix It

http-406-not-acceptableError

HTTP 406 Not Acceptable — What It Means & How to Fix It

http-407-proxy-authentication-requiredError

HTTP 407 Proxy Authentication Required — What It Means & How to Fix It

http-408-request-timeoutError

HTTP 408 Request Timeout — What It Means & How to Fix It

http-409-conflictError

HTTP 409 Conflict — What It Means & How to Fix It

http-410-goneError

HTTP 410 Gone — What It Means & How to Fix It

http-411-length-requiredError

HTTP 411 Length Required — What It Means & How to Fix It

http-412-precondition-failedError

HTTP 412 Precondition Failed — What It Means & How to Fix It

http-413-payload-too-largeError

HTTP 413 Payload Too Large — What It Means & How to Fix It

http-414-uri-too-longError

HTTP 414 URI Too Long — What It Means & How to Fix It

http-415-unsupported-media-typeError

HTTP 415 Unsupported Media Type — What It Means & How to Fix It

http-416-range-not-satisfiableError

HTTP 416 Range Not Satisfiable — What It Means & How to Fix It

http-417-expectation-failedError

HTTP 417 Expectation Failed — What It Means & How to Fix It

http-418-i-m-a-teapotError

HTTP 418 I'm a Teapot — What It Means & How to Fix It

http-421-misdirected-requestError

HTTP 421 Misdirected Request — What It Means & How to Fix It

http-422-unprocessable-entityError

HTTP 422 Unprocessable Entity — What It Means & How to Fix It

http-423-lockedError

HTTP 423 Locked — What It Means & How to Fix It

http-424-failed-dependencyError

HTTP 424 Failed Dependency — What It Means & How to Fix It

http-425-too-earlyError

HTTP 425 Too Early — What It Means & How to Fix It

http-426-upgrade-requiredError

HTTP 426 Upgrade Required — What It Means & How to Fix It

http-428-precondition-requiredError

HTTP 428 Precondition Required — What It Means & How to Fix It

http-429-too-many-requestsError

HTTP 429 Too Many Requests — What It Means & How to Fix It

http-431-request-header-fields-too-largeError

HTTP 431 Request Header Fields Too Large — What It Means & How to Fix It

http-451-unavailable-for-legal-reasonsError

HTTP 451 Unavailable For Legal Reasons — What It Means & How to Fix It

http-500-internal-server-errorCritical

HTTP 500 Internal Server Error — What It Means & How to Fix It

http-501-not-implementedCritical

HTTP 501 Not Implemented — What It Means & How to Fix It

http-502-bad-gatewayCritical

HTTP 502 Bad Gateway — What It Means & How to Fix It

http-503-service-unavailableCritical

HTTP 503 Service Unavailable — What It Means & How to Fix It

http-504-gateway-timeoutCritical

HTTP 504 Gateway Timeout — What It Means & How to Fix It

http-505-http-version-not-supportedCritical

HTTP 505 HTTP Version Not Supported — What It Means & How to Fix It

http-506-variant-also-negotiatesCritical

HTTP 506 Variant Also Negotiates — What It Means & How to Fix It

http-507-insufficient-storageCritical

HTTP 507 Insufficient Storage — What It Means & How to Fix It

http-508-loop-detectedCritical

HTTP 508 Loop Detected — What It Means & How to Fix It

http-510-not-extendedCritical

HTTP 510 Not Extended — What It Means & How to Fix It

http-511-network-authentication-requiredCritical

HTTP 511 Network Authentication Required — What It Means & How to Fix It

http-100Informational

HTTP 100 Continue — What It Means

http-101Informational

HTTP 101 Switching Protocols Explained

http-102Informational

HTTP 102 Processing — WebDAV Status

http-103Informational

HTTP 103 Early Hints — Preload Resources

http-201Informational

HTTP 201 Created — Resource Successfully Created

http-202Informational

HTTP 202 Accepted — Request Queued for Processing

http-204Informational

HTTP 204 No Content — Success with Empty Body

http-206Informational

HTTP 206 Partial Content — Range Request Response

http-207Informational

HTTP 207 Multi-Status — WebDAV Batch Response

http-300Informational

HTTP 300 Multiple Choices — Content Negotiation

http-302Warning

HTTP 302 Found — Temporary Redirect Explained

http-303Informational

HTTP 303 See Other — Redirect After POST

http-304Warning

HTTP 304 Not Modified — Browser Cache Still Valid

http-307Warning

HTTP 307 Temporary Redirect — Method Preserved

http-308Warning

HTTP 308 Permanent Redirect — Method Preserved

http-401Critical

HTTP 401 Unauthorized — Authentication Required

http-405Warning

HTTP 405 Method Not Allowed — Wrong HTTP Method

http-408Warning

HTTP 408 Request Timeout — Server Waited Too Long

http-409Warning

HTTP 409 Conflict — Resource State Conflict

http-410Warning

HTTP 410 Gone — Resource Permanently Removed

http-413Warning

HTTP 413 Payload Too Large — Request Body Exceeds Limit

http-415Warning

HTTP 415 Unsupported Media Type — Wrong Content-Type

http-422Warning

HTTP 422 Unprocessable Entity — Validation Error

http-429Critical

HTTP 429 Too Many Requests — Rate Limited

http-451Informational

HTTP 451 Unavailable For Legal Reasons

http-501Warning

HTTP 501 Not Implemented — Feature Not Supported

http-502Critical

HTTP 502 Bad Gateway — Upstream Server Error

http-504Critical

HTTP 504 Gateway Timeout — Upstream Server Slow

http-507Warning

HTTP 507 Insufficient Storage — Server Full

http-511Informational

HTTP 511 Network Authentication Required — Captive Portal

http-200-ok-explainedInformational

HTTP 200 OK — Successful Request Explained

http-203-non-authoritativeInformational

HTTP 203 Non-Authoritative Information — Proxy Modified Response

http-208-already-reportedInformational

HTTP 208 Already Reported — WebDAV Duplicate Suppression

http-226-im-usedInformational

HTTP 226 IM Used — Delta Encoding Applied

http-301-vs-302-redirectsInformational

HTTP 301 vs 302 Redirects — Permanent vs Temporary

http-305-use-proxy-deprecatedInformational

HTTP 305 Use Proxy — Deprecated Status Code

http-402-payment-required-modernWarning

HTTP 402 Payment Required — Reserved for Future Use

http-407-proxy-auth-requiredWarning

HTTP 407 Proxy Authentication Required — Proxy Login Needed

http-414-uri-too-long-fixWarning

HTTP 414 URI Too Long — Request URL Exceeds Server Limit

http-418-teapot-explainedInformational

HTTP 418 I'm a Teapot — Easter Egg Status Code

http-425-too-early-explainedInformational

HTTP 425 Too Early — TLS Early Data Rejected

http-503-retry-afterError

HTTP 503 Service Unavailable — Retry-After Explained

http-509-bandwidth-limit-exceededError

HTTP 509 Bandwidth Limit Exceeded — Unofficial Status Code

http-520-cloudflare-unknown-errorError

HTTP 520 Cloudflare — Web Server Returned an Unknown Error

http-522-cloudflare-connection-timed-outCritical

HTTP 522 Cloudflare — Connection Timed Out to Origin

http-206-partial-content-deep-diveInformational

HTTP 206 Partial Content — Range Requests & Resume Downloads

http-300-multiple-choices-explainedInformational

HTTP 300 Multiple Choices — Content Negotiation Guide

http-303-see-other-explainedInformational

HTTP 303 See Other — Post-Redirect-Get Pattern

http-307-temporary-redirect-guideInformational

HTTP 307 Temporary Redirect — Method-Preserving Redirect

http-308-permanent-redirect-guideInformational

HTTP 308 Permanent Redirect — Permanent Method-Preserving Redirect

http-409-conflict-deep-diveWarning

HTTP 409 Conflict — Resolving Resource State Conflicts

http-410-gone-seo-guideWarning

HTTP 410 Gone — Permanent Resource Removal & SEO Impact

http-411-length-required-fixWarning

HTTP 411 Length Required — Missing Content-Length Header

http-412-precondition-failed-fixWarning

HTTP 412 Precondition Failed — Conditional Request Rejected

http-413-payload-too-large-fixWarning

HTTP 413 Payload Too Large — Request Entity Size Limit

http-415-unsupported-media-type-fixWarning

HTTP 415 Unsupported Media Type — Content-Type Mismatch

http-416-range-not-satisfiable-fixInformational

HTTP 416 Range Not Satisfiable — Invalid Byte Range Request

http-417-expectation-failed-fixInformational

HTTP 417 Expectation Failed — Expect Header Rejected

http-421-misdirected-request-fixWarning

HTTP 421 Misdirected Request — TLS/HTTP2 Routing Error

http-422-unprocessable-entity-guideWarning

HTTP 422 Unprocessable Entity — Validation Error Handling

http-424-failed-dependency-fixWarning

HTTP 424 Failed Dependency — Cascading Request Failure

http-426-upgrade-required-fixWarning

HTTP 426 Upgrade Required — Protocol Upgrade Needed

http-428-precondition-required-fixWarning

HTTP 428 Precondition Required — Conditional Headers Mandatory

http-429-too-many-requests-rate-limitError

HTTP 429 Too Many Requests — Rate Limiting & Throttling Guide

http-431-header-fields-too-large-fixWarning

HTTP 431 Request Header Fields Too Large — Oversized Headers

http-451-unavailable-legal-reasonsError

HTTP 451 Unavailable For Legal Reasons — Content Censorship & Blocking

http-502-bad-gateway-deep-diveCritical

HTTP 502 Bad Gateway — Upstream Server Failure Analysis

http-504-gateway-timeout-deep-diveCritical

HTTP 504 Gateway Timeout — Backend Response Timeout Analysis

http-507-insufficient-storage-fixCritical

HTTP 507 Insufficient Storage — Server Disk Space Exhausted

http-508-loop-detected-fixError

HTTP 508 Loop Detected — Infinite Redirect or Binding Loop

http-102-processing-webdavInformational

HTTP 102 Processing — WebDAV Long-Running Request Indicator

http-208-already-reported-webdavInformational

HTTP 208 Already Reported — WebDAV Duplicate Binding Prevention

http-423-locked-webdavWarning

HTTP 423 Locked — WebDAV Resource Lock Conflict

http-cors-preflight-errors-guideError

CORS Preflight Errors — Access-Control-Allow-Origin Troubleshooting Guide

http-rate-limiting-429-strategiesWarning

HTTP Rate Limiting — 429 Too Many Requests Handling Strategies

http-caching-headers-guideInformational

HTTP Caching Headers — Cache-Control, ETag, and Expires Explained

http-content-negotiation-406-errorsWarning

HTTP Content Negotiation — 406 Not Acceptable and Accept Header Errors

http-range-request-206-416-errorsWarning

HTTP Range Requests — 206 Partial Content and 416 Range Not Satisfiable

http2-vs-http3-protocol-errorsError

HTTP/2 vs HTTP/3 Protocol Errors — QUIC, Stream, and Connection Failures

http-api-error-response-best-practicesInformational

API Error Responses — Standard Error Format and HTTP Status Code Selection

http-proxy-errors-502-504-guideError

HTTP Proxy Errors — 502 Bad Gateway and 504 Gateway Timeout Deep Dive

http-security-headers-guideWarning

HTTP Security Headers — HSTS, CSP, X-Frame-Options Complete Guide

http-redirect-chain-issuesWarning

HTTP Redirect Chains — 301/302 Loop Detection and SEO Impact

http-websocket-upgrade-errorsError

HTTP WebSocket Upgrade Errors — 101 Switching Protocols Failures

http-authentication-schemes-401Warning

HTTP Authentication Schemes — 401 Basic, Bearer, Digest, and OAuth Errors

http-etag-conditional-requestsInformational

HTTP ETag and Conditional Requests — If-None-Match and 304 Not Modified

http-multipart-upload-errorsWarning

HTTP Multipart Upload Errors — File Upload Failures and Size Limits

http-connection-keep-alive-errorsWarning

HTTP Keep-Alive Connection Errors — Persistent Connection Troubleshooting

http-ssl-tls-handshake-errorsCritical

HTTP SSL/TLS Handshake Errors — Certificate and Protocol Failures

http-graphql-error-handling-patternsWarning

GraphQL Error Handling — Best Practices for API Error Responses

http-webhook-delivery-errorsError

Webhook Delivery Errors — Troubleshooting Failed HTTP Callbacks

http-server-sent-events-errorsWarning

Server-Sent Events Errors — SSE Connection and Streaming Failures

http-api-versioning-errorsWarning

API Versioning Errors — Breaking Changes and Compatibility Issues

http-multipart-form-data-errorsWarning

Multipart Form Data Errors — File Upload HTTP Request Failures

http-options-preflight-errorsError

HTTP OPTIONS Preflight Errors — CORS Preflight Request Failures

http-chunked-transfer-encoding-errorsWarning

Chunked Transfer Encoding Errors — Streaming Response Failures

http-expect-100-continue-errorsInformational

HTTP 100 Continue Errors — Expect Header Request Flow Issues

http-proxy-authentication-errorsWarning

HTTP 407 Proxy Authentication — Corporate Proxy Authorization Failures

http-content-disposition-errorsInformational

Content-Disposition Header Errors — File Download Naming and Handling Issues

http-retry-after-header-implementationWarning

Retry-After Header — Rate Limiting and Service Unavailable Recovery

http-vary-header-caching-issuesInformational

Vary Header Misuse — Cache Fragmentation and CDN Caching Problems

http-alt-svc-protocol-errorsInformational

Alt-Svc Protocol Errors — HTTP Alternative Service Connection Failures

http-103-early-hints-errorsInformational

HTTP 103 Early Hints — Preloading and Link Header Configuration Issues

http-feature-policy-violationsWarning

Feature Policy Violations — Permissions-Policy Header Errors in Browsers

http-referrer-policy-errorsInformational

Referrer-Policy Errors — Missing Referrer Data and Privacy Header Issues

http-cross-origin-embedder-policy-errorsWarning

Cross-Origin Embedder Policy — COEP Blocking Resources and SharedArrayBuffer

http-link-header-pagination-errorsInformational

Link Header Pagination — REST API Pagination Header Implementation Errors

http-if-modified-since-caching-errorsInformational

If-Modified-Since Caching — Conditional Request and 304 Not Modified Errors

http-patch-method-semantics-errorsInformational

HTTP PATCH Semantics — Partial Update Request Errors and Best Practices

http-head-request-handling-errorsInformational

HTTP HEAD Request Errors — Response Header Mismatch and Implementation Issues

http-accept-ranges-byte-serving-errorsWarning

Accept-Ranges Byte Serving — Range Request and Partial Content Download Errors

http-rest-api-status-code-best-practicesInformational

REST API Status Codes — Choosing the Right HTTP Status Code for API Responses

http-trailer-headers-errorsInformational

HTTP Trailer Headers — Chunked Response Metadata and Checksum Errors

http-content-negotiation-errorsInformational

Content Negotiation Errors — Accept Header and 406 Not Acceptable Responses

http-521-web-server-is-down-cloudflareCritical

HTTP 521 Web Server Is Down — Cloudflare Origin Server Unreachable

http-523-origin-is-unreachable-cloudflareCritical

HTTP 523 Origin Is Unreachable — Cloudflare Cannot Resolve Origin DNS

http-524-a-timeout-occurred-cloudflareError

HTTP 524 A Timeout Occurred — Cloudflare Origin Response Timeout

http-525-ssl-handshake-failed-cloudflareError

HTTP 525 SSL Handshake Failed — Cloudflare Origin SSL Negotiation Error

http-526-invalid-ssl-certificate-cloudflareError

HTTP 526 Invalid SSL Certificate — Cloudflare Origin Certificate Validation Failed

http-grpc-status-code-unavailableError

gRPC Status UNAVAILABLE — Service Temporarily Unreachable or Overloaded

http-grpc-status-code-deadline-exceededWarning

gRPC Status DEADLINE_EXCEEDED — Request Timeout Before Completion

http-oauth2-invalid-grant-errorError

OAuth2 invalid_grant Error — Token Refresh and Authorization Code Failures

http-jwt-token-expired-errorWarning

JWT Token Expired Error — JSON Web Token Expiration and Renewal

http-api-rate-limit-429-too-many-requestsWarning

API Rate Limit 429 Too Many Requests — Handling Rate Limiting Headers

http-cloudfront-502-bad-gateway-errorError

AWS CloudFront 502 Bad Gateway — Origin Connection and Response Errors

http-vercel-edge-function-timeoutWarning

Vercel Edge Function Timeout — Serverless Execution Time Limit Exceeded

http-api-gateway-504-integration-timeoutError

AWS API Gateway 504 Integration Timeout — Lambda or Backend Response Too Slow

http-content-security-policy-violationWarning

Content-Security-Policy Violation — CSP Blocked Resource Loading Error

http-hsts-strict-transport-security-errorError

HSTS Strict-Transport-Security Error — HTTPS Enforcement and Preload Issues

http-webhook-delivery-failure-retryWarning

Webhook Delivery Failure — Retry Logic and Endpoint Reliability Patterns

http-openapi-validation-request-body-errorInformational

OpenAPI Request Validation Error — Schema Mismatch and Type Errors

http-api-key-authentication-401-errorWarning

API Key Authentication 401 — Invalid, Missing, or Expired API Key Errors

http-100-continue-expect-header-issuesInformational

HTTP 100 Continue Expect Header Issues — What It Means & How to Fix It

http-418-hyper-text-coffee-pot-control-protocolInformational

HTTP 418 HTCPCP Teapot Protocol — What It Means & How to Fix It

http-440-login-timeout-iisWarning

HTTP 440 Login Timeout (IIS) — What It Means & How to Fix It

http-449-retry-with-iisWarning

HTTP 449 Retry With (IIS) — What It Means & How to Fix It

http-460-aws-elb-client-closed-connectionWarning

HTTP 460 Client Closed Connection (AWS ELB) — What It Means & How to Fix It

http-463-aws-alb-too-many-x-forwarded-forWarning

HTTP 463 Too Many X-Forwarded-For IPs (AWS ALB) — What It Means & How to Fix It

http-530-cloudflare-error-1xxxError

HTTP 530 Cloudflare Error 1XXX — What It Means & How to Fix It

http-499-client-closed-request-nginxWarning

HTTP 499 Client Closed Request (Nginx) — What It Means & How to Fix It

http-520-cloudflare-unknown-error-detailedError

HTTP 520 Unknown Error (Cloudflare) — Detailed Debugging Guide

http-api-gateway-403-missing-auth-tokenWarning

AWS API Gateway 403 Missing Authentication Token — What It Means & How to Fix It

http-api-gateway-502-malformed-lambdaError

AWS API Gateway 502 Malformed Lambda Proxy Response — What It Means & How to Fix It

http-561-unauthorized-aws-elbError

HTTP 561 Unauthorized (AWS ELB) — What It Means & How to Fix It

http-api-pagination-cursor-invalidInformational

API Pagination Cursor Invalid Error — What It Means & How to Fix It

http-graphql-query-complexity-limitWarning

GraphQL Query Complexity Limit Exceeded — What It Means & How to Fix It

http-websocket-1006-abnormal-closureError

WebSocket 1006 Abnormal Closure — What It Means & How to Fix It

http-cloudfront-403-request-blockedWarning

CloudFront 403 Request Blocked — What It Means & How to Fix It

http-grpc-status-code-internalError

gRPC Status Code 13 INTERNAL — What It Means & How to Fix It

http-oauth2-token-refresh-failedError

OAuth2 Token Refresh Failed Error — What It Means & How to Fix It

http-vercel-function-timeout-504Error

Vercel Serverless Function Timeout 504 — What It Means & How to Fix It