http-status

# HTTP Status Code Reference Instant lookup for any HTTP status code — meaning, common causes, and how to fix it. Full data table in `references/codes.md`. Zero dependencies, fully offline. ## When to use - "What does 429 mean?" - "I'm getting a 502 from my API, what's wrong?" - "What's the difference between 401 and 403?" - "Which 5xx errors are retryable?" - "What does Cloudflare 524 mean?" --- ## Code ranges (quick orientation) ``` 1xx Informational — request received, continue processing 2xx Success — request was received, understood, accepted 3xx Redirection — further action needed to complete the request 4xx Client Error — request contains bad syntax or cannot be fulfilled 5xx Server Error — server failed to fulfil an apparently valid request ``` --- ## Lookup procedure 1. Check `references/codes.md` for the exact code 2. If not found, infer from the range (4xx = client error, 5xx = server error) 3. Note the source category: RFC standard / WebDAV / Nginx / Cloudflare / unofficial 4. Return: meaning + common causes + recommended action --- ## Output format ### Single code lookup ``` 🔢 HTTP 429 — Too Many Requests ━━━━━━━━━━━━━━━━━━━━ Category: 4xx Client Error Standard: RFC 6585 Meaning: The user has sent too many requests in a given time (rate limiting). Common causes: • API rate limit exceeded • Burst traffic hitting a throttling policy • Forgot to handle Retry-After header What to do: • Check the Retry-After response header for wait time • Implement exponential backoff in your client • Review your request frequency and add throttling logic • Consider caching responses to reduce request volume Related codes: 503 (server overloaded) ``` ### Comparison query ``` 🔢 401 vs 403 ━━━━━━━━━━━━━━━━━━━━ 401 Unauthorized → Authentication is required and has failed or not been provided → "You need to log in first" → Fix: provide valid credentials / token 403 Forbidden → Server understood the request but refuses to authorize it → "You're logged in but don't have permission" → Fix: check user roles/permissions, contact admin Key difference: 401 = identity unknown (not authenticated) 403 = identity known but access denied (not authorized) ``` ### Retryable codes ``` ✅ Generally safe to retry (with backoff): 408 Request Timeout 429 Too Many Requests ← respect Retry-After header 500 Internal Server Error ← transient server issues 502 Bad Gateway ← upstream temporarily unavailable 503 Service Unavailable ← server overloaded/maintenance 504 Gateway Timeout ← upstream timeout ❌ Do NOT retry blindly: 400 Bad Request ← fix your request first 401 Unauthorized ← re-authenticate first 403 Forbidden ← retrying won't help 404 Not Found ← resource doesn't exist 422 Unprocessable Entity ← fix validation errors first ``` --- ## Notes - For Nginx-specific codes (444, 494-499) and Cloudflare codes (520-530), see `references/codes.md` - 418 "I'm a teapot" is a real RFC 2324 status — implemented as an Easter egg in some servers - Some codes (e.g. 103, 425, 451) are newer and may not be supported by all clients/proxies