The Short Version

Shopify Scripts (2016-2026) let Shopify Plus merchants write Ruby code that runs during checkout to modify prices, shipping, and payments. They're hosted by Shopify and edited in a browser-based Script Editor.

Shopify Functions (2023+) replace Scripts with a modern, sandboxed architecture. You write JavaScript (compiled to WebAssembly), deploy via the Shopify CLI, and target specific APIs like Discounts, Delivery Customization, or Payment Customization.

Deadline: Script Editor stops working June 30, 2026. All Ruby scripts will be disabled.

Architecture Comparison

Feature	Scripts (Old)	Functions (New)
Language	Ruby (custom sandbox)	JavaScript → WebAssembly
Editor	Browser-based Script Editor	Local IDE + Shopify CLI
Deployment	Paste in admin, publish	`shopify app deploy`
Hosting	Shopify-managed	Shopify-managed (Wasm sandbox)
Execution	Full Ruby interpreter	Sandboxed Wasm (no network, no fs)
Performance	5-10ms typical	<5ms (Wasm is fast)
Data Access	Full cart object (Ruby)	GraphQL input query (you define what you need)
Network Access	None	None (but can read metafields)
Plan Required	Shopify Plus only	All plans (via apps)
Availability	Deprecated June 2026	Active, expanding

What Shopify Functions Can Do That Scripts Couldn't

Available to all plans. Scripts were Plus-only. Functions work through apps available to all merchants.
Faster execution. Wasm sandboxes execute in <5ms. Ruby scripts were slower and harder to optimize.
Better developer experience. Write in your preferred IDE. Test locally. Version control. CI/CD.
Type-safe inputs. GraphQL input queries mean you know exactly what data you'll get.
Metafield-driven configuration. Store config in metafields, change behavior without redeploying code.

What Scripts Could Do That Functions Can't (Yet)

Free-form price modification. Scripts could set any price. Functions have more structured discount types.
In-browser editing. Script Editor was simple for non-developers. Functions require CLI and deployment.
Dynamic metaprogramming. Ruby's eval, define_method, etc. don't translate to Functions.

API Mapping: Script Type → Function Target

Line Item Scripts → Multiple APIs

This is where it gets complex. A single Line Item Script might map to Product Discounts (price changes), Order Discounts (order-level rules), Cart Transform (bundles, GWP), or Cart Validation (blocking items). ScriptShift detects which patterns map where.

Shipping Scripts → Delivery Customization

Relatively clean mapping. Hide, rename, and reorder shipping rates. Note: you cannot change rate prices directly (use shipping discounts for that).

Payment Scripts → Payment Customization

Cleanest mapping. Hide, rename, and reorder payment methods based on cart contents, customer, or address.

Migration Timeline Recommendation

NowAudit all active scripts. Use ScriptShift to analyze complexity.

Mar 2026Generate migration code. Set up dev store for testing.

Apr 2026Test Functions on dev store. Compare behavior with original Scripts.

May 2026Deploy Functions to production. Run in parallel with Scripts for validation.

Jun 30, 2026Script Editor disabled. Functions must be live.

Migrate your scripts in minutes, not months

ScriptShift analyzes your Ruby scripts and generates ready-to-deploy Function code. Free.

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