Stop sending mail to bad addresses. This flow checks each new contact in your CRM, marks if the address can receive mail, and flags records that need a fix. It suits teams that run direct mail or rely on clean contact data.

It begins when your CRM posts a webhook to n8n with the contact id and address fields. The Set Address Fields node maps the incoming data. The Address Verification request sends the street, city, state, and zip to Lob and gets a deliverability result. A Switch node reads that result. If deliverable, an HTTP request adds a verified tag in your CRM. If not deliverable, another HTTP request adds a different tag that can start a follow up action for your team. Other fields pass through so you can keep the record intact.

To run it, you need a Lob account and a webhook listener in your CRM. Expect faster list cleanup, fewer returned mail pieces, and clear routing for human review. Common uses include new lead capture, list imports from events, and preparing contacts for print campaigns. Setup takes a few minutes once your URLs and API key are ready.

• Webhook trigger captures new contact data from your CRM
• Set node maps address, address2, city, state, and zip into clean fields
• HTTP request calls Lob US Verifications to check deliverability
• Switch node routes records based on the verification result
• HTTP requests tag the contact in your CRM for deliverable and not deliverable outcomes
• Other incoming fields pass through so the full record stays intact

• Reduce manual address checks from 2 minutes per contact to zero
• Improve mail deliverability by up to 30 percent
• Reduce address entry errors by up to 70 percent
• Automate 100 percent of tagging and routing for new contacts
• Scale to validate thousands of contacts per day
• Connect your CRM and Lob without custom code

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 Groundhogg and Lob. See the Tools Required section above for links to create accounts with these services.
3. Open the CRM Webhook Trigger node in n8n and copy the Test URL. Keep the node open so n8n can listen for a test request.
4. In your Groundhogg funnel or CRM webhook settings, create a POST webhook that sends id, address, address2, city, state, and zip to the n8n webhook URL when a new contact is created.
5. If your field names differ, open the Set Address Fields node and map your incoming field names to address, address2, city, state, and zip. Leave Include Other Fields enabled so extra data passes through.
6. Open the Address Verification node. In the Credential dropdown, click Create new credential, then follow the on screen instructions to add your Lob Basic Auth API key. Use your Lob API key as the credential value.
7. Check the Address Verification response in the n8n execution preview. Note the field that indicates deliverability, then open the Switch node and set the condition to match the deliverable value.
8. In Groundhogg, create two webhook listener steps or endpoints that can add tags to a contact. Copy each listener URL into the Update Groundhogg Deliverable and Update Groundhogg NOT Deliverable nodes.
9. Confirm the body parameters in both update nodes include tag and id. Make sure the id variable references the id from the webhook trigger output.
10. Test the full flow: send a known valid address and confirm the deliverable tag appears on the contact. Then send an invalid address and confirm the not deliverable tag and any follow up automation start as expected.
11. Troubleshoot: if Lob returns 401 or 403, recheck your API key and credential type. If tags are not added, verify the Groundhogg webhook URLs and that the id matches a real contact. If routing is wrong, inspect the verification response and adjust the Switch condition.