Missing OAuth Redirect URL for Slack Integration in n8n

Below is some guidance to help you troubleshoot the missing OAuth Redirect URL for your Slack credentials:

Verify the Credential Type

Make sure you’re actually configuring your Slack credentials using OAuth2 rather than the API access token method. The OAuth Redirect URL only appears when you select OAuth2. If you’re using an API access token, the redirect URL is not required and thus isn’t shown.

Self-Hosted vs. Cloud Considerations

• Self-Hosted Installation:
  When you’re self-hosting n8n, the OAuth Redirect URL is generated in the credential settings when you choose OAuth2. Verify that your instance is correctly configured and that you’re looking at the correct credential type. Sometimes a browser refresh or clearing cache can resolve display issues.

• n8n Cloud/Trial Version:
  If you are using the trial version on the cloud, note that n8n Cloud manages OAuth setups differently. Often the OAuth Redirect URL is preconfigured behind the scenes and might not be shown directly in the UI. In this case, the redirect URL is already registered with the service (Slack in your case), and you may need to refer to the documentation or onboarding guide for n8n Cloud about configuring OAuth credentials.

Steps to Resolve

1. Switch to OAuth2 (if not already selected):
   In your Slack credential configuration, select the OAuth2 authentication method. This should trigger the display of the OAuth Redirect (or Callback) URL.

2. Double-check Your n8n Instance:
   Ensure your n8n instance’s configuration (domain or host settings) is correct. Self-hosted instances need the proper settings to generate and display the correct redirect URL.

3. Consult Environment-Specific Documentation:
   If you’re on n8n Cloud during the trial, review any cloud-specific instructions or FAQs regarding OAuth credential configuration. Cloud users might have the OAuth Redirect URL pre-registered, and you might not see it explicitly in your credentials UI.

Final Notes

If after these steps the OAuth Redirect URL still isn’t visible, consider the following:

• Confirm that your browser isn’t blocking any scripts that might hide or delay the rendering of the OAuth URL.
• Check the n8n community forums or documentation updates for any known issues with your version (n8n@1.79.0) related to OAuth display.

Following these troubleshooting steps should help you identify why the OAuth Redirect URL is missing and allow you to configure your Slack integration properly. If the issue persists, consider reaching out to the n8n community for further assistance.