HTTP Status Code & Response Checker
Inspect live server HTTP response headers, check redirects, and search complete HTTP status codes dictionary.
Check Live Website HTTP Status & Response Time
HTTP Status Code Reference & Glossary
Filter and search all standard RFC status codes
The request has succeeded. Standard response for successful HTTP GET, POST, or HEAD requests.
The request succeeded and a new resource has been created as a result, common after POST / PUT API calls.
The target resource has been assigned a new permanent URI. Crucial for SEO link equity transfer (90-99% PageRank pass).
The requested URI resides temporarily under a different location. Search engines will not transfer link authority permanently.
The server cannot or will not process the request due to perceived client syntax error, invalid formatting, or deceptive routing.
The request has not been applied because it lacks valid authentication credentials for the target resource.
The server understands the request but refuses to authorize it (permission restrictions, IP blocks, or firewall rules).
The server cannot find the requested resource. Links that lead to 404 are called dead/broken links and should be fixed.
The user has sent too many requests in a given amount of time ("rate limiting"). Includes Retry-After header.
A generic error message, given when an unexpected condition was encountered by the server (e.g. fatal PHP error, DB crash).
The server, while acting as a gateway or proxy (e.g. Nginx, Cloudflare), received an invalid response from upstream server.
The server is currently unable to handle the request due to a temporary overloading or maintenance of the server.
Complete Guide to HTTP Status Codes & Search Engine Optimization
HTTP status codes are standard three-digit server response signals defined by the Internet Engineering Task Force (RFC 9110). They communicate whether a client's web request was successfully completed, redirected, blocked by permissions, or failed due to backend server infrastructure crashes.
The 5 HTTP Status Classes
- 1xx (Informational): Request received, continuing process (e.g. 101 Switching Protocols).
- 2xx (Success): Request successfully received, understood, and accepted (e.g. 200 OK, 201 Created).
- 3xx (Redirection): Further action must be taken to complete request (e.g. 301 Permanent, 302 Found).
- 4xx (Client Errors): Bad request syntax or resource missing (e.g. 400 Bad Request, 403 Forbidden, 404 Not Found, 429 Too Many Requests).
- 5xx (Server Errors): Server failed to fulfill valid request (e.g. 500 Internal Error, 502 Bad Gateway, 503 Unavailable).
Critical SEO & Crawl Budget Rules
- 301 vs. 302 Redirects: Always use
301 Moved Permanentlyfor canonical migrations to pass over 95%+ PageRank equity. Use 302 strictly for temporary A/B experiments. - 404 vs. 410 Gone: Return
410 Gonefor intentionally deleted content to instruct Googlebot to remove the URL from search index immediately without repeated re-crawls. - Prevent Redirect Chains: Chained hops (A > B > C) add 500ms+ Time to First Byte (TTFB) latency and drain crawl budget.
Frequently Asked Questions (FAQs)
How do 500 and 503 errors damage search rankings?
When Googlebot receives persistent 500 Internal Server Error responses, it immediately slows down its crawl rate to avoid overloading your backend server. If outages persist beyond 24 to 48 hours, Google will drop the URLs from search index. For scheduled maintenance, always return 503 Service Unavailable with a Retry-After header.
What causes a 502 Bad Gateway or 504 Gateway Timeout?
A 502 Bad Gateway occurs when an edge reverse proxy (such as NGINX or Cloudflare) receives an invalid or terminated response from an upstream backend app server (PHP-FPM, Node.js). A 504 Gateway Timeout occurs when the backend takes longer than the proxy timeout threshold (e.g. 60 seconds) to respond.
What is HTTP 429 Too Many Requests?
HTTP 429 indicates rate-limiting: the user or bot has sent too many requests in a given amount of time. Web APIs frequently return 429 to protect against DDoS attacks and brute-force scrapers.