HTTP Status Code Lookup Tutorial
Detailed guide, best practices, and FAQ
Use Cases
The HTTP Status Code Lookup is useful for frontend/backend development, API debugging, ops troubleshooting, and HTTP learning. When you see an unfamiliar status code in DevTools or curl output, this tool gives you bilingual explanations instantly.
Features
- Comprehensive: 60+ standard and extended codes across 1xx/2xx/3xx/4xx/5xx
- Instant search: filter by code, name, or description keyword
- Category filter: one-click filter by 1xx-5xx
- Bilingual: each entry has both Chinese and English explanations
- One-click copy: click any card to copy the code to clipboard
Examples
Example 1: Scenario 1: Frontend gets a 401; search "401" to confirm it means Unauthorized, prompting a re-login.
Example 2: Scenario 2: Ops sees a 502/504; search to confirm gateway issue (upstream failure or timeout), deciding whether to restart the service or contact upstream.
Example 3: Scenario 3: When learning HTTP, click "4xx" to browse all client errors and understand the difference between 401/403/404.
Best Practices
- Memorize common codes: 200 (OK), 301 (Moved Permanently), 304 (Not Modified), 404 (Not Found), 500 (Internal Server Error), 503 (Service Unavailable)
- Distinguish 401 vs 403: 401 means unauthenticated (need login), 403 means authenticated but no permission
- Distinguish 301 vs 302: 301 is permanent (SEO juice transferred), 302 is temporary (no transfer)
- 4xx is client-side (check params/auth), 5xx is server-side (contact backend)
FAQ
Why are some codes unfamiliar to me?
This tool includes standard RFC 9110 codes plus WebDAV, HTTP/2, etc. extensions (e.g., 207, 421, 425), which are rare in real projects but included for completeness.
What is 418 I'm a Teapot?
An April Fools status code defined in RFC 2324 (HTCPCP), never actually used but a programmer culture meme.
How to memorize 1xx-5xx categories?
1 Informational, 2 Success, 3 Redirection, 4 Client Error, 5 Server Error.