Shopify Scripts stopped running. Here is where each script’s logic goes now.

If a discount, a shipping rule or a payment rule stopped working in your checkout on June 30, 2026, check whether it was a Shopify Script. Shopify stopped editing and publishing Scripts on April 15, 2026, and all Scripts stopped executing on June 30, 2026. Scripts that were still published were deactivated.

Start with what you actually had

The Shopify admin has a Scripts customizations report. It lists the customizations that were active before the deprecation, grouped as payment gateways, shipping and product discounts. Use it as the inventory for the migration, rather than memory or old code.

For each entry, write down the rule in plain words: which carts it applied to, what it changed, and why it existed. Some rules turn out to be covered by Shopify’s built-in discounts or an existing App Store app. The rest need a Shopify Function.

Where each script type goes

Two differences matter when you rebuild. Delivery options can be renamed, but the carrier name stays in front of the new title. And when you reorder shipping options, the cheapest option must stay the one selected by default.

The constraints that decide the build

• Plan. Stores on any plan can use App Store apps that contain Functions, but only Shopify Plus stores can use a custom app that contains Functions. Without Plus, the logic has to come from an app on the Shopify App Store. Some capabilities also need Plus whichever kind of app you use: payment terms, and Cart Transform lineUpdate (also available on development stores).
• Data. A Function receives only what its GraphQL input query asks for. It cannot read the clock or generate random values. Data it needs, such as tiers or thresholds, usually comes from metafields or cart attributes.
• Size and speed. Functions run inside checkout with fixed limits, including a 256 kB compiled binary. Shopify recommends Rust for performance; JavaScript and TypeScript are also supported.
• Limits per store. A store can activate at most 25 delivery customization functions and 25 payment customization functions.

What else Functions can do

The migration is also a chance to revisit the rules themselves. The Cart and Checkout Validation API can block a checkout with a clear error, for example a quantity limit. On Shopify Plus stores, the Payment Customization API can also set payment terms, such as net terms for business buyers. When a Function reads its settings from a metafield, a threshold can change without a code change.

A sensible order of work

1. Open the Scripts customizations report and write each rule in plain words.
2. Mark each rule as built-in discount, App Store app, or custom Function.
3. Check the plan: custom Functions need Shopify Plus.
4. Build and test each Function on a development store with realistic carts, then install it on the live store.
5. Compare checkout totals against orders from before June 30 for the same kinds of cart.