HTTP 101 Switching Protocols vs 102 Processing
Both HTTP 101 (Switching Protocols) and 102 (Processing) belong to the 1xx Informational category. 101 indicates that the server understands the Upgrade header field request and indicates which protocol it is switching to. Meanwhile, 102 means that the server has received and is processing the request, but no response is available yet. Prevents the client from timing out.
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 received and is processing the request, but no response is available yet. Prevents the client from timing out.
When You See It
During long-running WebDAV operations.
How to Fix
Wait for the final response. This is an interim status to prevent timeouts.
Key Differences
HTTP 101: The server understands the Upgrade header field request and indicates which protocol it is switching to.
HTTP 102: The server has received and is processing the request, but no response is available yet. Prevents the client from timing out.
You encounter 101 when when upgrading from HTTP/1.1 to WebSocket, or to HTTP/2.
You encounter 102 when during long-running WebDAV operations.
When to Use Which
For 101 (Switching Protocols): This is normal behavior during protocol upgrades. Ensure your client supports the target protocol. For 102 (Processing): Wait for the final response. This is an interim status to prevent timeouts.