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, Authentication, retry, cache
HTTP status code list
Select a code to display its meaning and practical considerations.
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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.
- Use comparison or copying as needed.
Notes
- 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.
Registered value reference: IANA HTTP Status Code Registry /Basic specifications: RFC 9110