Keep your mail campaigns on track by checking contact addresses before you send. New or updated contacts are checked for deliverable mail status, and your CRM is updated so your team knows what to do next. Great for direct mail, postcards, welcome kits, and renewal notices.

A webhook receives contact data from your CRM. The workflow maps the address fields, then calls a mail address verification service to validate street, city, state, and zip. The result includes a deliverability status. A decision step routes the outcome: if deliverable, a tag is added in Keap to mark the record as verified; if not deliverable, a different tag is applied to trigger follow up by your team or another automation. This reduces returned mail and keeps your database clean.

Set up is simple. You will need a mail verification account and an API key, plus a Keap connection in n8n. Map your CRM fields to the request, send a test record, and confirm the correct tag is applied. Expect fewer returns, faster mail prep, and clearer next steps for your team. Ideal for list cleaning, event invites, and subscription box shipping.

• Webhook intake captures contact and address fields from your CRM
• Field mapping step standardizes address, address2, city, state, and zip for the request
• HTTP request posts to a US address verification endpoint using API credentials
• Decision logic checks the deliverability value returned by the verification service
• Keap tag update for deliverable results to mark verified records
• Keap tag update for non deliverable results to trigger manual review or outreach
• Clear sticky notes guide setup for credentials and tagging strategy

• Reduce manual checks from 10 minutes per contact to under 1 minute
• Lower returned mail by validating addresses before printing
• Improve data quality with clear tags for deliverable and non deliverable records
• Connect CRM webhooks with Keap and a verification service in one flow
• Scale mail operations as contact volume grows without extra staff

1. Import the template into n8n: Create a new workflow in n8n > Click the three dots menu > Select 'Import from File' > Choose the downloaded JSON file.
2. You'll need accounts with Keap, Lob and Webhook.site. See the Tools Required section above for links to create accounts with these services.
3. Create a Lob account and generate an API key in the Lob dashboard. Keep the key ready for Basic Auth.
4. In n8n, open the HTTP Request node named Address Verification. In Credential to connect with, click Create new credential, choose HTTP Basic Auth, and enter your Lob API key as the username and leave the password blank if required by Lob. Save the credential.
5. Connect Keap in n8n: open each Keap node. In Credential to connect with, click Create new credential and follow the on screen steps to sign in with your Keap account. Name the credential clearly so your team recognizes it.
6. Configure your CRM to send a POST webhook to the path shown in the CRM Webhook Trigger node. Use the exact URL provided by n8n when the workflow is active.
7. Check the Set Address Fields node to confirm the input fields match your webhook payload keys for address, address2, city, state, and zip.
8. Send a test payload from your CRM or use Webhook.site to mirror the payload and confirm n8n receives the request. Look for successful execution through the Address Verification node.
9. Verify the HTTP response includes a deliverability field. Confirm the Switch node routes deliverable results to the correct Keap tag node and non deliverable results to the other tag node.
10. In Keap, make sure the tags Mailing Address Deliverable and Mailing Address NOT Deliverable exist. If needed, update the tag names in the Keap nodes to match your exact tag names or IDs.
11. Run another test and check the contact record in Keap. You should see the correct tag added based on the address check.
12. Troubleshoot common issues: if the webhook does not trigger, confirm the path and method are correct. If the verification call fails, recheck Lob credentials and required fields. If tags do not apply, confirm the contactId mapping uses the id from the webhook payload.