Passing 'chatInput' and 'output' between n8n and Open Web UI (N8N Pipe) : hit and miss

[Jon_Ontario]

In a simple Integration, my Open WebUI pipe function connects to a Mistral Chat Model. Sometimes it works. When I add the Postgres Chat Memory integration, the response back to Open WebUI fails - even though I may see a response in the ‘Respond to Webhook’ node. Results seem to be hit and miss. The chatInput field is sometimes good, or it may include the entire chat history, or it may be empty. Often the n8n workflow completes error free, but Open WebUI will complain " Error: 404 - {“code”:404,“message”:“The requested webhook "JVnew" is not registered”

At this point, n8n doesn’t generate an error message but it looks like the ‘chatInput’ and ‘response’ fields (and sometimes ‘sessionId’) aren’t being populated or handled correctly.

Please share your workflow

(Select the nodes on your canvas and use the keyboard shortcuts CMD+C/CTRL+C and CMD+V/CTRL+V to copy and paste the workflow.)

Share the output returned by the last node

Information on your n8n setup

• n8n version: “NODE_VERSION=22.16.0”, “YARN_VERSION=1.22.22”,
• Database (default: SQLite): Postgres Chat Memory
• n8n EXECUTIONS_PROCESS setting (default: own, main):
• Running n8n via (Docker, npm, n8n cloud, desktop app): Docker. Each has its own container - n8n, Open WebUI etc.. and they connect using host.docker.internal
• Operating system: Windows