In your Merge account, go to Advanced -> Webhooks -> Third-party Webhooks. Make sure "Allow automatic webhook creation" is enabled.

Once the Intercom account has been linked, check if you are using Intercom partnership authentication. Go to Integrations -> Ticketing and find Intercom. If the "I'm a Intercom Partner..." box is checked and there are credentials entered, you are using partner authentication. If it is not checked, you are not.

Example partner authentication configuration

Example NOT using partner authentication

If you are NOT using partnership authentication follow this step ONLY and ignore the rest. If you are using partnership authentication, continue with all steps.

Go to the Intercom linked account and enable all the webhooks you are require.

The Intercom receiving webhook set up is complete if you are NOT using partnership authentication!

If you are using partnership authentication, expand a webhook event in Merge and copy the Merge Receiver URL. (Note the signature key will be a random string. You can ignore this)

Next, go to your Intercom developer account and find your application. Go to Webhooks and click "Edit". Paste the URL from the previous step into the Endpoint URL field.

Last, add the specific topics (webhook events you require). This should match the enabled webhook event types in Merge. Click "Save".

Your Intercom receiving webhook set up is complete!