Mail a Welcome Postcard to Merchants After Shopify App Installation

When a merchant installs your Shopify app and subscribes (starts paying), Mantle fires this webhook with the customer's basic information including {{mantle.id}}. You need to specify your Mantle app ID in the appIds field—this is found in your Mantle dashboard under your app settings. The trigger only fires for subscriptions to the specified app, ensuring postcards are sent only for the correct app if you manage multiple apps through Mantle.

This step retrieves the full customer record from Mantle using {{mantle.id}} from the trigger. It fetches comprehensive customer data including {{mantle_1.customer.name}}, {{mantle_1.customer.appInstallations[0].app.displayName}}, and the complete billing address fields: {{mantle_1.customer.billingAddress.address1}}, {{mantle_1.customer.billingAddress.address2}}, {{mantle_1.customer.billingAddress.city}}, {{mantle_1.customer.billingAddress.provinceCode}}, {{mantle_1.customer.billingAddress.zip}}, and {{mantle_1.customer.billingAddress.country}}.

This address information ensures the postcard is mailed to the correct business location.

This step sends a 4x6 postcard via Thanks.io using the merchant's billing address from {{mantle_1.customer}}.

You need to configure several fields during setup:
(1) Size—select postcard size (typically 4x6),
(2) Front image URL—provide the full URL to your branded postcard front design (must be publicly accessible),
(3) Handwriting style—choose from Thanks.io's available handwriting styles, and
(4) Message—the default message welcomes the merchant to your app family and is personalized with {{mantle_1.customer.appInstallations[0].app.displayName}} for your app name. The message text can be fully customized to match your brand voice while staying within Thanks.io's character limits. The postcard is addressed to {{mantle_1.customer.name}} and mailed to their complete billing address.