How can I create YouTube API credentials for self-hosted n8n on a local network without a domain?

Below is an explanation of what’s happening and some suggestions on how to resolve the issue.

Why This Issue Occurs

n8n automatically builds its OAuth redirect URL using configuration values (N8N_PROTOCOL, N8N_HOST, and N8N_PORT) or the WEBHOOK_URL if it’s set. When you run n8n on your local network (using an IP address) the generated URL (for example, http://192.168.x.x:5678/rest/oauth2-credential/callback) is used in the Google OAuth flow.

However, Google’s OAuth setup for external users does not accept IP addresses as valid redirect URIs. Google requires a proper domain name (or sometimes “localhost” for testing) when you register your OAuth client. As you noted, the built-in redirect URL in n8n (which often shows “localhost:5678”) comes from the default configuration as used by n8n Cloud. Changing the webhook URL using your .env file (i.e. setting WEBHOOK_URL) is the typical workaround when running behind a reverse proxy, but that only works if you can supply a valid, resolvable domain as your webhook URL.

How to Solve It

Because you do not have a dedicated domain right now, here are a few possible workarounds:

1. Use a Tunneling Service (e.g. ngrok):
   Set up a tunnel so that your local n8n instance is accessible via a public URL. For example, running ngrok can provide you with a subdomain like https://your-subdomain.ngrok.io.

   • Update your n8n configuration to set the webhook URL to the ngrok URL. For example:

     BASHCopied
     export WEBHOOK_URL=https://your-subdomain.ngrok.io/

   • In the Google Cloud Console, register the redirect URL as:

     https://your-subdomain.ngrok.io/rest/oauth2-credential/callback
     

2. Use a Dynamic DNS Service:
   You can register for a free or low-cost dynamic DNS service (like DuckDNS) that assigns you a domain name.

   • Configure your router or Raspberry Pi to update your dynamic DNS domain.
   • Set your WEBHOOK_URL in n8n to use that domain (e.g., https://yourdomain.duckdns.org/).
   • Use the corresponding full redirect URL in Google Cloud Console:

     https://yourdomain.duckdns.org/rest/oauth2-credential/callback
     

3. Using Service Accounts (if applicable):
   If your workflow supports using a service account instead of OAuth2 (and if your node is compatible), you could use a Google Service Account. This method avoids the redirect URL requirement altogether. However, be aware this method is generally more complex and may not support all use cases.

Summary

Your problem is that Google refuses to accept an IP address for the OAuth redirect URL. n8n generates this URL based on your instance’s configuration, and when self-hosted behind an IP address (or when using the default “localhost:5678”), Google’s OAuth consent screen will reject it. The simplest solutions are to use a public URL via a tunneling service or register for a dynamic DNS domain so that you have an acceptable domain name for Google’s requirements.

Following one of the above approaches should allow you to successfully add new credentials for the YouTube API in your self-hosted n8n instance.

Below is an explanation of what’s happening and how you might resolve it:

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What’s the Issue?

n8n automatically uses a fixed OAuth Redirect URL (by default containing localhost:5678 and the callback path) when creating Google (including YouTube) API credentials. Since you’re running n8n on a local IP (192.168.x.x) behind Nginx on your Raspberry Pi, this fixed URL doesn’t match your setup. Unfortunately, the OAuth settings in Google Cloud don’t let you add an IP-based URL as an authorized redirect URI—they only accept proper domain names or “localhost” URLs.

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What Causes the Problem?

• Fixed OAuth Redirect URL: n8n’s Google OAuth credentials (used for popular services like YouTube) expect the callback URL to use the domain configured (it’s hardcoded as “localhost:5678/rest/oauth2-credential/callback” in the workflow setup).
• Domain vs. IP Mismatch: Google Cloud’s OAuth consent and redirect configuration does not accept IP addresses in the callback URL (only proper domains like “example.com” or “localhost”).

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How Can You Work Around This?

Since you don’t have your own domain or a dedicated public server, here are a couple of approaches:

1. Use a Custom Domain with Local DNS Override:

   • Create a Local Domain Name: You can set up a custom domain (for example, using a free dynamic DNS service or manually editing your local hosts file) that points to your Raspberry Pi’s IP.
   • Update n8n’s Webhook URL: Configure your instance to use this custom domain by setting the WEBHOOK_URL environment variable in your .env file. For example:

     BASHCopied
     export WEBHOOK_URL=https://my-custom-domain.local/

   • Adjust Google Console Settings: Once you have a domain, set the OAuth redirect URI in the Google Cloud Console to match your new domain (e.g. https://my-custom-domain.local/rest/oauth2-credential/callback).

2. Use a Tunnel Service:

   • Ngrok (or similar): You can use a tunneling service like ngrok which provides a public URL that forwards to your local instance.
   • Configure n8n and Google OAuth: Use the public URL provided by ngrok as your WEBHOOK_URL and then set the matching redirect URI in your Google credentials. This lets you bypass the restrictions on using local IP addresses.

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Summary

The root of your issue is that n8n’s fixed OAuth Redirect URL (using localhost:5678) does not work with Google OAuth when the service is accessed via an IP address on your local network. Since Google doesn't accept IP addresses in the callback URL, you’ll need to either set up a custom domain (even locally via DNS or hosts file) or use a tunneling service to provide a valid public URL. Adjust the WEBHOOK_URL accordingly so that both n8n and the Google Cloud OAuth configuration are aligned.

This should enable you to create YouTube API credentials successfully within your self-hosted n8n instance.