HTTP Status Code Reference
Look up any HTTP status code — meaning, typical causes and how to fix it.
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What is HTTP Status Code Reference?
Every HTTP response carries a three-digit status code: 2xx success, 3xx redirect, 4xx client error, 5xx server error. Knowing what 409 means versus 422, or when a 302 is the wrong choice versus 307, is the difference between fixing an API problem in minutes and chasing the wrong layer for an hour.
This reference lists every standard code with a plain-English meaning, the typical situations that produce it, and the fix usually required. It is a searchable dictionary — type the code or a keyword and jump straight to the entry.
How to use it
- 1Type a code (like 429) or a keyword (like 'rate') into the search box.
- 2Read the meaning, typical causes and suggested fix for the code.
- 3Follow the cross-references to related codes (401 vs 403, 301 vs 308).
Common use cases
- Deciding the correct status for a new API endpoint (409 vs 422 vs 400).
- Debugging a failing integration: what is the third party's 403 actually saying?
- Training new team members on REST conventions with a concrete reference.
Frequently asked questions
▸What is the difference between 401 and 403?
401 means 'unauthenticated' — you need to log in or send valid credentials. 403 means 'authenticated but not allowed' — the server knows who you are and still refuses. Mixing them up is one of the most common API design mistakes.
▸Should I return 400 or 422 for validation errors?
422 (Unprocessable Content) is the semantically precise choice for well-formed but invalid data; many APIs still use 400 for simplicity. Either is defensible — consistency inside your API matters more.