HTTP 101 Switching Protocols vs 226 IM Used
HTTP 101 (Switching Protocols) is a 1xx Informational response, while 226 (IM Used) is a 2xx Success response. 101 indicates that the server understands the Upgrade header field request and indicates which protocol it is switching to. In contrast, 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 server understands the Upgrade header field request and indicates which protocol it is switching to.
When You See It
When upgrading from HTTP/1.1 to WebSocket, or to HTTP/2.
How to Fix
This is normal behavior during protocol upgrades. Ensure your client supports the target protocol.
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
101 is a 1xx Informational response, while 226 is a 2xx Success response.
HTTP 101: The server understands the Upgrade header field request and indicates which protocol it is switching to.
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 101 when when upgrading from HTTP/1.1 to WebSocket, or to HTTP/2.
You encounter 226 when when using delta encoding to reduce bandwidth.
When to Use Which
For 101 (Switching Protocols): This is normal behavior during protocol upgrades. Ensure your client supports the target protocol. For 226 (IM Used): Rarely encountered. The response uses Instance Manipulations (IM) as specified.