List of HTTP status codes, meanings, and countermeasures
You can search for HTTP 100 to 511 registration codes and find out the cause, things to check on the client/server side, and the concept of retries and caching.
Search by code, name, and meaning
/You can also move to the search field using the key. Example:404, Additional information for this feature., retry, cache
HTTP status code list
Select a code to display its meaning and practical considerations.
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Additional information for this feature.Compare similar code
You can check codes that are easy to use, such as 301 and 308, 401 and 403, 429 and 503, side by side.
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About this tool
View status codes for use in HTTP response investigation, API design, troubleshooting, and web server configuration, with references to IANA registration information and RFCs.
Features
- Codes from 1xx to 5xx registered with IANA
- Search for codes, English names, Japanese names, meanings, and related headers
- Cause, countermeasure, retry, cache, comparison of similar code
- Copy code, response examples, and Markdown
How to use
- Search for codes and error messages.
- Select the target code from the list and check the details.
- Copy
Additional information for this feature.
- We do not include non-standard code specific to frameworks, CDNs, or web servers.
- For the actual cause and countermeasures, please also check the response body, header, server log, and specifications of the service being used.
- When retrying, consider the idempotency of the HTTP method, duplication of processing, Retry-After, and backoff.
Additional information for this feature. IANA HTTP Status Code Registry /Basic specifications: RFC 9110
About this tool
You can check the meaning and practical measures of HTTP status codes used in API development, web server settings, and browser error investigation.
Features
- IANA registered 1xx to 5xx codes, English name, Japanese name, RFC reference
- Search, classification/use filter, similar code comparison, response example/Markdown copy
How to use
- Search by code, name, meaning, and related headers.
- Select the target code from the list and read the cause and check points on the client/server side.
- Copy
Limitations
- Non-standard code uniquely defined by frameworks or CDNs is not included.
- Please also check the response text, header, server log, and specifications of the service being used to determine the actual cause of the failure.
Privacy: Search, compare, and copy are done within the browser; your searches are not sent or saved to the Develop Tools server.