Getting 400 error in my HTTP module while trying to upload a document to my Voiceflow Knowledge Base

[Gaspar_Bekes-Varro]

What is your goal?

Uploading a document to my Voiceflow Knowledge Base

What is the problem & what have you tried?

These are the settings for the Http module with the 400 Error:

• Authentication type: no authentication
• URL: https://realtime-api.voiceflow.com/v1alpha1/public/knowledge-base/document
• Method: POST
  Header 1: Name: Authorization Value: [my Voiceflow API key]
  Query parameters: empty
• Body content type: application/JSON
• Body input method: JSON string
• Body content: a message generated by ChatGPT (in JSON format)
• Parse response: no

Error messages or input/output bundles

This is the error I get:
{“message”:“Invalid request body”,“statusCode”:400,“statusText”:“Bad Request”,“timestamp”:“2026-04-13T13:36:10.397Z”,“path”:“/v1alpha1/public/knowledge-base/document”}

[mszymkowiak]

Hello,

Please take a look at the Voiceflow’s documentation.

If you are using application/json as the body content type, you should provide a URL to the document.
If you want to upload the file directly, please use multipart/form-data.

Documentation:

Create document - Voiceflow Documentation

The documentation can be misleading, as the body type switch is not clearly visible:

And HTTP module config:

Have a nice day,
Michal