TillKit UK Postcode Rules lets a Shopify store block or change checkout and delivery options by postcode. This page says what the app stores and why.
The app keeps no customer data. At checkout, Shopify Functions that run on Shopify's servers read the delivery postcode, address lines and country, the items in the cart, the cart's total, the shopper's language and the delivery options, only to apply the store's rules: the postcode and country to match its areas, and the address lines to spot a PO box. They keep nothing. No orders, addresses or payment details reach the app. Shopify's customer data request and customer deletion notices, which carry a customer's id, email and phone number, pass through the app's server, where they are checked in memory and dropped without being stored or logged, as there is nothing held to return or delete.
Nothing is sold or shared. The app uses Cloudflare to host its pages and its session database, and Shopify to run the checkout functions. The app keeps no request logs. Its own short logs hold the store's domain and any error the app hits, never customer data, and Cloudflare keeps them for up to 7 days. When a store asks for help, the developer can read that store's saved rules and the app's log lines naming it to trace the problem. Neither holds customer data.
Uninstalling the app deletes the store's sessions straight away. Shopify's shop data deletion request deletes them too. The database's own recovery history drops them within 30 days. The rules live in the store's own Shopify data, and the app keeps no copy of them.
Questions about this policy: hello@tillkit.app.