How to Set Up Split Delivery with Google Workspace and ImprovMX

Split delivery allows Google Workspace to handle mail for known users and forward unknown or unrecognised recipients to another mail server—like ImprovMX. This guide walks you through setting it up using the Google Admin Console.

Before you begin: This configuration is best suited to more technical users, and you'll need full admin access to the Google Workspace account.

Ensure your domain’s MX records are pointing to Google with a higher priority than ImprovMX. It's recommended to disable the Strict MX Verification feature so you won't be alerted about the low priority MX records.

Step 1: Add the ImprovMX Mail Route

Follow Google’s official guide for Step 1 to navigate to the Routing section in the Google Admin Console.

When prompted to add a mail route, fill in the dialog as shown:

Mail Route Configuration:

  • Name: ImprovMX

  • Change dropdown to: Multiple Hosts

  • Primary Host: mx1.improvmx.com : 25 (Load %: 100)

  • Secondary Host: mx2.improvmx.com : 25 (Load %: 100)

  • ✅ Require mail to be transmitted via a secure (TLS) connection

  • ✅ Require CA-signed certificate

  • ✅ Validate certificate hostname

Click Test TLS connection. If successful, click Save.

Step 2: Set Up Split Delivery Rule

Once the route is created, proceed to set up the actual routing policy.

Follow Step 2 of the Google guide to get to the appropriate Routing section, then configure as below:

Routing name: ImprovMX Routing

Email Messages to Affect:

  • ✅ Inbound

  • ⬜ Outbound

  • ⬜ Internal – sending

  • ✅ Internal – receiving

Actions to Perform:

  • Route > ✅ Change the route → Select ImprovMX

  • ⬜ Also reroute spam

  • ⬜ Suppress bounces from this recipient

Apply To:

  • ✅ Account types: Unrecognised/catch-all

Leave other options (headers, subject, envelope, etc.) unmodified unless required by your setup.

Final Step: Save and Verify

Once saved, Google will:

  • Attempt to deliver mail to existing users in Google Workspace first

  • Forward unrecognised recipients to ImprovMX via the route you set. Make sure you set up your aliases as needed!

💬 Need Help?

If you run into any issues or have further questions, feel free to reach out to us at support@improvmx.com.

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