# Mail a Welcome Postcard to Merchants After Shopify App Installation 13 min setup No coding required Runs automatically Build customer loyalty and stand out from competitors by mailing a postcard when a merchant installs your Shopify app. Triggered upon installation, MESA will check for a complete billing address and, if available, automatically send a personalized postcard to the customer. This unexpected, tangible gesture creates a memorable first impression, enhances brand perception, and encourages long-term engagement. ## How it works 3 steps to send handwritten welcome postcards to new Shopify app installers ### New App Subscriber App connector: [Mantle](/content/apps/mantle/integrate "View Mantle integration page"/index.html)• Time to complete: 2 minutes **Why this matters:** This trigger captures new paying subscribers at the moment they commit to your app, enabling you to make a memorable first impression while their excitement and engagement are at their peak. 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. ### Retrieve Customer App connector: [Mantle](/content/apps/mantle/integrate "View Mantle integration page"/index.html)• Time to complete: 1 minute **Why this matters:** Fetches the complete customer profile including billing address and app details needed to personalize and properly mail the postcard, ensuring it reaches the right person at the right location. This step retrieves the full customer record from Mantle using the customer ID from the trigger. It fetches comprehensive customer data including the customer's name, app installation details, and the complete billing address fields needed to mail the postcard. This address information ensures the postcard is mailed to the correct business location. ### Send Postcard App connector: [Thanks.io](/content/apps/thanks/integrate "View Thanks.io integration page"/index.html)• Time to complete: 10 minutes **Why this matters:** Creates and mails a physical, handwritten postcard that differentiates your app through personal touch, building stronger emotional connections and brand recall than purely digital onboarding. This step sends a 4x6 postcard via Thanks.io using the merchant's billing address retrieved in the previous step. 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 and can be fully customized to match your brand voice while staying within Thanks.io's character limits. **Frequently asked questions** ### What if a merchant's billing address is incomplete or invalid? The Thanks.io step may fail if required address fields are missing or invalid. Consider adding a filter step before the postcard action to check that key address fields (address line 1, city, zip, country) are not empty, and log any failed sends for manual follow-up. ### How much do postcards cost through Thanks.io? Postcard pricing varies by Thanks.io plan and postcard size/style. Check your Thanks.io account for current pricing. Consider adding filters to send postcards only to higher-value subscribers if cost per send is a concern. ### Can I preview what the postcard will look like before sending? Yes, run a test or manually trigger the workflow with test data, but stop the workflow before the Thanks.io step executes. Review the formatted message and verify your front image URL displays correctly. Thanks.io also provides previews in their dashboard when you upload handwriting samples and images. ## Make this template your own! Customize this workflow even further: - Include a promo code or special offer - Modify the message to include a unique discount code for premium features or add-ons, turning the welcome postcard into a conversion tool that drives upgrades while building goodwill. - Send only to specific plan tiers - Track postcard delivery status - Follow up with email after delivery ## You're in good company Avg. App Store rating 4.9/5 Merchant reviews 157 Avg. time saved per week 3.5 hrs "MESA has been a game changer for us. And, if you ever get stuck, their support team is always super helpful." **PetFriendly** "It's like Zapier but exactly designed for Shopify. I have been able to complete all the workflows that I've needed." **Zailys** "The MESA team has been amazing at helping us set up our automations. We would highly recommend this app!" **Rothy's** ## Ready to send handwritten welcome postcards to new Shopify app installers? 7-day free trial • 13 min setup • Cancel anytime [Start with this template — It's free](/content/pricing?template=mantle%2Fcustomer%2Fsend_postcard_when_merchant_installs_shopify_app&templateName=send-postcard-after-shopify-app-installation "Install and use this template in MESA - Free to use"/index.html) Need help? Our automation experts will help you personalize this workflow for free.