HTTP 203 Non-Authoritative Information vs 303 See Other
HTTP 203 (Non-Authoritative Information) is a 2xx Success response, while 303 (See Other) is a 3xx Redirection response. 203 indicates that the response payload has been modified by a transforming proxy from the origin server's 200 response. In contrast, 303 means that the server is redirecting to a different resource using GET, typically after a POST operation (Post/Redirect/Get pattern).
説明
The response payload has been modified by a transforming proxy from the origin server's 200 response.
このコードが表示される場合
When a proxy or CDN modifies the response body (e.g., adds headers, transforms content).
解決方法
Check if a proxy is modifying the response. Access the origin directly if you need the original content.
説明
The server is redirecting to a different resource using GET, typically after a POST operation (Post/Redirect/Get pattern).
このコードが表示される場合
After form submissions to prevent resubmission on browser refresh.
解決方法
Follow the Location header with a GET request. This is intentional — part of the PRG pattern.
主な違い
203 is a 2xx Success response, while 303 is a 3xx Redirection response.
HTTP 203: The response payload has been modified by a transforming proxy from the origin server's 200 response.
HTTP 303: The server is redirecting to a different resource using GET, typically after a POST operation (Post/Redirect/Get pattern).
You encounter 203 when when a proxy or CDN modifies the response body (e.g., adds headers, transforms content).
You encounter 303 when after form submissions to prevent resubmission on browser refresh.
どちらをいつ使うか
For 203 (Non-Authoritative Information): Check if a proxy is modifying the response. Access the origin directly if you need the original content. For 303 (See Other): Follow the Location header with a GET request. This is intentional — part of the PRG pattern.