HTTP Status Codes Reference
Quickly lookup and understand web server response codes and their meanings.
The Definitive HTTP Status Codes Guide: Decoding Server Responses
Every time you visit a website, your browser and the server engage in a silent conversation via HTTP Status Codes. These 3-digit numbers are the DNA of web communication, signaling success, redirection, or critical errors. At Anand Design's DevBox, we have compiled this comprehensive HTTP Status Code Reference to help developers debug APIs and SEOs optimize crawl budgets with surgical precision.
Why Status Codes are the Foundation of Technical SEO
Googlebot relies entirely on status codes to understand how to index your site. A misplaced 404 (Not Found) on a high-traffic page can kill your rankings, while a 301 (Permanent Redirect) ensures your link equity remains intact during migrations. Using our SEO Engine v1.1 architecture, we’ve categorized these codes into five distinct classes to streamline your troubleshooting workflow.
2xx: Success Signals
3xx: Redirection Logic
4xx & 5xx: Error Handling
The Five Classes of HTTP Responses
1xx: Informational (Request Received)
These codes indicate that the server has received the request and is continuing the process.
Key Code: 101 Switching Protocols — essential for WebSocket connections.
2xx: Success (Mission Accomplished)
The action was successfully received, understood, and accepted.
Key Code: 200 OK — the gold standard for healthy web pages.
3xx: Redirection (Moving Day)
Further action must be taken to complete the request.
Key Code: 301 Permanent Redirect — critical for maintaining SEO during URL changes.
4xx: Client Error (It’s You, Not Me)
The request contains bad syntax or cannot be fulfilled.
Key Code: 403 Forbidden — when the server understands the request but refuses to authorize it.
5xx: Server Error (It’s Me, Not You)
The server failed to fulfill an apparently valid request.
Key Code: 503 Service Unavailable — often seen during maintenance or server overload.
Quick Debugging Reference Table
| Code | Meaning | SEO/Dev Action |
|---|---|---|
| 302 | Found (Temporary) | Use only for short promos; doesn't pass link equity. |
| 401 | Unauthorized | Check API keys or Auth headers in your request. |
| 410 | Gone | Tells Google to permanently remove the URL from index. |
| 500 | Internal Server Error | Check server logs; usually a code crash or PHP error. |
Webmaster FAQ
What is the difference between a 301 and 302 redirect?
A 301 redirect is permanent and tells search engines to transfer all ranking power to the new URL. A 302 is temporary and search engines will keep the old URL indexed.
How do 404 errors affect my website?
While occasional 404s are normal, a high volume of broken links can degrade user experience and signal poor maintenance to search engine crawlers.
Global Response Indexing & Semantic Metadata
Core Reference
- • HTTP Status Codes List
- • Web Response Guide
- • Server Status Meanings
- • HTTP Error Codes Hub
Redirection SEO
- • 301 vs 302 Redirect
- • Canonical Tag Logic
- • Permanent Redirect Code
- • SEO Crawl Errors
Dev Debugging
- • API Response Codes
- • Fix 500 Internal Error
- • Debug 403 Forbidden
- • Rest API Status List
Brand Focus
- • Anand Design DevBox
- • SEO Suite v1.1
- • Professional Web Utils
- • Free Dev Resources
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