Persistent "valid dictionary or object" error with webhook | callin.io Community

The error “Input should be a valid dictionary or object to extract fields from” isn’t coming from Hunch—it’s due to how the Custom Action is set up in callin.io. Postman accepts raw JSON, but in callin.io the body must be a properly structured object.

Steps to check:

1. In the Custom Action, set the Body type to JSON (not raw text).

    

   {
"tool_id": "123",
"input": {
"url": "{{Formatter.url}}"
}
}


2. Explicitly add the headers:

    

   Content-Type: application/json
Authorization: Bearer {{API_KEY}}


3. Don’t wrap the JSON in quotes (avoid sending it as an escaped string).

4. First test with hardcoded values that work in Postman, then swap them for Slack/Formatter variables.

With that setup, the request should behave exactly like in Postman and return the uid.