HTTP 203 Non-Authoritative Information vs 226 IM Used
Both HTTP 203 (Non-Authoritative Information) and 226 (IM Used) belong to the 2xx Success category. 203 indicates that the response payload has been modified by a transforming proxy from the origin server's 200 response. Meanwhile, 226 means that the server has fulfilled a GET request for the resource, and the response is a representation of the result of one or more instance-manipulations.
Description
The response payload has been modified by a transforming proxy from the origin server's 200 response.
When You See It
When a proxy or CDN modifies the response body (e.g., adds headers, transforms content).
How to Fix
Check if a proxy is modifying the response. Access the origin directly if you need the original content.
Description
The server has fulfilled a GET request for the resource, and the response is a representation of the result of one or more instance-manipulations.
When You See It
When using delta encoding to reduce bandwidth.
How to Fix
Rarely encountered. The response uses Instance Manipulations (IM) as specified.
Key Differences
HTTP 203: The response payload has been modified by a transforming proxy from the origin server's 200 response.
HTTP 226: The server has fulfilled a GET request for the resource, and the response is a representation of the result of one or more instance-manipulations.
You encounter 203 when when a proxy or CDN modifies the response body (e.g., adds headers, transforms content).
You encounter 226 when when using delta encoding to reduce bandwidth.
When to Use Which
For 203 (Non-Authoritative Information): Check if a proxy is modifying the response. Access the origin directly if you need the original content. For 226 (IM Used): Rarely encountered. The response uses Instance Manipulations (IM) as specified.