Keep your direct mail clean by checking addresses the moment a new contact arrives. The flow flags good and bad addresses inside HighLevel so you can send with confidence and fix issues fast.

A webhook receives contact data from your CRM. A Set step maps street, unit, city, state, and postal code into clean fields. An HTTP Request sends those fields to Lob US Verifications to confirm deliverability. A Switch reads the deliverability value and routes the result to two HighLevel updates. The contact gets a tag for Mailing Address Deliverable or Mailing Address NOT Deliverable using the email and phone from the webhook payload. This keeps your CRM tidy and triggers the right follow up.

You will need a Lob account with an API key and access to HighLevel. Point your CRM to the n8n webhook URL and send a POST with address fields. Expect fewer returned letters, faster list cleanup, and better reporting on address quality. Teams that run mailers, ship welcome kits, or depend on precise customer records will see quick wins and less rework.

• Webhook intake captures new contact data from your CRM with a POST request
• Field mapping step standardizes address, unit, city, state, and postal code
• Address check uses Lob US Verifications to confirm deliverability and correct formatting
• Conditional routing reads the deliverability flag and splits good vs not deliverable
• HighLevel updates apply clear tags for deliverable and not deliverable contacts
• Email and phone from the webhook are used to match and update the right contact

• Reduce manual address checks from minutes per record to seconds with automated validation
• Improve mailing data accuracy by 40 to 70 percent through verified addresses
• Cut returned mail costs by 30 percent by catching bad addresses before print and ship
• Streamline list cleanup by routing not deliverable records to a follow up queue
• Connect two key systems without custom code to keep data consistent

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 GoHighLevel and Lob. See the Tools Required section above for links to create accounts with these services.
3. Open the CRM Webhook Trigger node and copy the Production Webhook URL. In your CRM, create a webhook that sends a POST request to this URL whenever a new contact is added or updated.
4. Ensure your CRM sends these fields in the JSON body: address, address2, city, state, and postal_code, as well as email and phone for matching in HighLevel.
5. Double click the Lob HTTP Request node. In the Credential field, click Create new credential and follow the on screen steps. In your Lob dashboard, create a Live or Test API key and use Basic Auth with the API key as the username and an empty password if prompted.
6. Confirm the HTTP Request node points to https://api.lob.com/v1/us_verifications and uses POST with the mapped fields primary_line, secondary_line, city, state, and zip_code.
7. Open the Set Address Fields node and verify each mapping pulls from the webhook JSON. Make sure postal_code maps to zip_code for the Lob request body.
8. Open both GoHighLevel nodes. In the credential dropdown, click Create new credential and follow the on screen instructions to connect your GoHighLevel account. Name the credential clearly, for example GoHighLevel Main.
9. In each GoHighLevel node, confirm Email and Phone are set to the values from the webhook. Set the tags to match your naming standards, for example Mailing Address Deliverable and Mailing Address NOT Deliverable.
10. Check the Switch node rule. It should evaluate the deliverability field and send records to the deliverable branch when the value equals deliverable and to the other branch when it does not.
11. Send a test POST from your CRM or a tool like Postman with a real address. Watch the execution in n8n and confirm the Lob response includes deliverability and that the correct tag is applied in GoHighLevel.
12. If the request fails, verify the Lob API key, confirm Basic Auth is set, and check that city, state, and zip fields are not empty. If tags are not showing, confirm the email or phone matches an existing GoHighLevel contact.