HTTP 101 Switching Protocols vs 204 No Content
HTTP 101 (Switching Protocols) is a 1xx Informational response, while 204 (No Content) 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, 204 means that the server successfully processed the request but is not returning any content. Common for DELETE operations and form submissions that don't need a response body.
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 successfully processed the request but is not returning any content. Common for DELETE operations and form submissions that don't need a response body.
When You See It
After DELETE requests, PUT updates where no body is needed, or CORS preflight responses.
How to Fix
No fix needed. The action was successful; there is simply no content to return.
Key Differences
101 is a 1xx Informational response, while 204 is a 2xx Success response.
HTTP 101: The server understands the Upgrade header field request and indicates which protocol it is switching to.
HTTP 204: The server successfully processed the request but is not returning any content. Common for DELETE operations and form submissions that don't need a response body.
You encounter 101 when when upgrading from HTTP/1.1 to WebSocket, or to HTTP/2.
You encounter 204 when after DELETE requests, PUT updates where no body is needed, or CORS preflight responses.
When to Use Which
For 101 (Switching Protocols): This is normal behavior during protocol upgrades. Ensure your client supports the target protocol. For 204 (No Content): No fix needed. The action was successful; there is simply no content to return.