OAuth2 Integration Issue with Bullhorn – Auth Code Not Captured by n8n

[Carlsch]

Dear community,

I’m reaching out regarding an OAuth2 integration issue we’re experiencing between n8n and Bullhorn’s REST API.

We’ve been working with Bullhorn Support, and after manually testing the OAuth2 flow (Authorization Code Grant), they’ve confirmed the following:

• The client_id and API user (n8n.api) are correctly configured on Bullhorn’s side.

• They are able to manually generate an authorization code via the browser when using this URL: Bullhorn | Log in

• The code appears as expected in the URL after login and consent.

• However, when running the OAuth2 process via n8n, the platform fails to retain or extract the authorization code, and instead shows this error: “Unsupported content type: text/html;charset=utf-8”

Bullhorn suspects the issue may be due to n8n expecting the authorization code in the body of the response, while Bullhorn (in line with OAuth2 standards) places it in the redirect URL (?code=...), as outlined in their documentation.

They also provided this link to their official OAuth2 Quick Start documentation:

Get Started with the Bullhorn REST API

Request for Support

Could you please review how n8n is handling the OAuth2 Authorization Code Flow in this context?

Specifically:

• Does n8n expect the code to be present in the body of the response rather than the redirect URL?
• Can n8n be configured to correctly handle providers like Bullhorn that follow the standard ?code=... redirect model?
• Is there a known workaround or custom credential configuration that allows n8n to handle this properly?

This issue is currently blocking a production integration between our Bullhorn instance and automated workflows in n8n. Any guidance or workaround would be greatly appreciated.

[dbert]

I have a similar issue with the Bullhorn auth process. Have you identified a solution to this?