This blog covers what Shopify Scripts are, why Shopify is deprecating them, and the two critical deadlines every merchant needs to act on: the April 15, 2026 freeze (no new Scripts or edits after this date) and the June 30, 2026 full shutdown (Scripts stop executing permanently, with no rollback).
This blog covers the two paths to migrate from Shopify Scripts to Shopify Functions: using a Functions-native app like Kite, Fly: Bundles & Cross Sell, or Easy Bundle Builder for standard discount and bundle logic with no code required, or building a custom Shopify Function for highly store-specific logic that no app covers.
This blog covers a step-by-step migration process: how to audit your active Scripts using Shopify's Customizations Report, how to match each Script type to its Functions replacement, how to build or configure your replacement, how to test in parallel without disrupting live customers, and how to cut over safely before the deadline.
This blog covers the discount stacking behavior change that catches Shopify Plus merchants off guard (Functions run in isolation, unlike Scripts which had full cart control), the runtime data restrictions that affect Scripts pulling from external sources, and how to handle performance considerations for large carts and broad collection logic.
Shopify is evolving, and so should your store. With Shopify's decision to deprecate Scripts in favor of Shopify Functions, merchants have an opportunity to upgrade their store's discount offerings and checkout experience, improve scalability, and future-proof their Shopify store.
Whether you're a Shopify Plus merchant, a freelancer/developer who has set up Scripts for your clients, or a Shopify Agency that manages Plus stores, migrating from Shopify Scripts to Functions is mandatory.
This guide will walk you through the why, what, and how of this transition, ensuring your store remains functional and optimized.
What Were Shopify Scripts?
Shopify Scripts consisted of lightweight Ruby snippets executed server-side during checkout on Plus plans. They analyzed inputs such as cart items, buyer attributes (like tags or location), available shipping rates, and payment methods, then modified outputs like item pricing, delivery choices, or gateway visibility. Housed in the Script Editor app, they enabled brands to deliver highly targeted checkout experiences without relying on third-party servers or complex integrations. Shopify Scripts have long been the backbone of custom checkout experiences for Shopify Plus merchants. Since you are now migrating from Shopify Scripts to Functions, lets first read into what scripts actually helped you do.
Script template selection options
What Are Shopify Functions?
Shopify Functions are the replacement for Scripts. These arecompiled WebAssembly modules that run directly on Shopify's infrastructure. Instead of mutating a shared cart object in Ruby, a Function receives a snapshot of cart or checkout state and returns a set of operations. Faster, more predictable, and available on all Shopify plans (not just Shopify Plus). The key shift: Functions execute in under 5ms with no cold starts, and they work across all Shopify plans when used via a Shopify Functions compatible Shopify app.
Functions cover every customization type Shopify Scripts handled, plus new capabilities. Here's what the Shopify Scripts to Function migration gets you:
Control which location fulfills an order — net new capability
With Shopify Functions, you gain flexibility, scalability, and compatibility with Shopify’s latest development tools.
PRO TIP: Instead of migrating from Shopify Scripts to Functions via Code, use apps already built on the powerful Shopify Scripts platform such as Kite Discount & Free Gift.
Why Is Shopify Deprecating Scripts?
Scripts were built for a different era of Shopify Ruby-based, Plus-exclusive, and difficult to scale. As Shopify's infrastructure modernized around GraphQL APIs and WebAssembly, Scripts became the bottleneck they were never designed to outlast.
The Shopify Scripts to Functions migration gives every merchant (not just Shopify Plus) access to powerful checkout customization, while giving Shopify a single, performant execution layer to maintain.
Shopify Scripts vs. Shopify Functions
Shopify Scripts
Shopify Functions
Language
Ruby (mruby subset)
Any language → WebAssembly (JS, Rust most common)
Execution
Server-side, interpreted, variable speed
Compiled WASM, consistent sub-5ms, no cold starts
Available to
Shopify Plus only
All plans (public app) / Plus only (custom app)
External data at runtime
Limited
Not allowed — data must be pre-synced to metafields
Discount stacking
Full control within one script
Each Function runs in isolation; one product discount per line item
Deployment
Script Editor in Shopify Admin
Deployed as part of a Shopify app (public or private)
Network calls
Supported
Not supported — stateless input/output only
Scalability
Degrades under high traffic
Built for high-volume, no performance ceiling
Replacement Shopify Functions for Every Shopify Script
Legacy Script Function
Replacement Shopify function
Core Modifications
Line item/pricing
Discount Functions
Item/order/shipping adjustments, bundles
Shipping management
Delivery Functions
Rate visibility, ordering, conditions
Payment handling
Payment Functions
Gateway show/hide/reordering
Cart adjustments
Cart Transform Functions
Line merges/splits, pre-checkout tweaks
Rule enforcement
Functions + workflow apps
Blocks and compliance checks
Key Dates to Remember (Shopify Scripts to Functions Migration):
Date
What Happens
April 15, 2026
Scripts freeze — no new Scripts can be published, existing ones can no longer be edited
June 30, 2026
Full shutdown — all Scripts stop executing permanently. No rollback.
The April 15 2026 freeze is the more urgent deadline. After that date, if something breaks in a live Script, you cannot fix it, you can only replace it with a Function.
If you do nothing: your Scripts don't migrate automatically. They simply stop running on June 30, 2026. Any discount logic, shipping rule, or payment customization built on Scripts will silently break at checkout.
Two Ways to Migrate from Shopify Scripts to Shopify Functions
When it comes to migrating from Shopify Scripts to Shopify Functions, you have two paths. Which one is right for you depends on the complexity of your Scripts.
Path 1: Use a Shopify App Built on Shopify Functions (Recommended)
If your Scripts handle discounts, free gifts, BOGO offers, tiered pricing, bundles, shipping rules, or payment customizations there's almost certainly an app that already does this natively on Shopify Functions. No code, no developer, no deployment pipeline.
This is the right path if:
Your Scripts run standard promotional logic (volume discounts, BOGO, free gift with purchase, bundle pricing)
You want to be migrated before the April 15, 2026 freeze without a development project
You want to add capabilities your Scripts never had — like a progress bar, cart-level upsells, or campaign scheduling
For line item scripts i.e. discounts, free gifts, BOGO, tiered pricing:
Kite: Discounts & Free Gifts is built entirely on Shopify Functions and replaces line item Scripts with a no-code setup. You get every promotional type your Script was handling plus campaign scheduling, customer tag targeting, and a native progress bar without writing a single line of code. No hacks.
Recreate your Script's logic inside the app's no-code interface
Test against your live Script in parallel
Unpublish the Script once verified
Path 2: Build a Custom Shopify Function
If your Scripts contain highly store-specific logic — custom stacking rules, external data dependencies, or conditions no app can replicate — you'll need to build a custom Function. This requires a developer and familiarity with Shopify CLI, JavaScript or Rust, and WebAssembly.
This is the right path if:
Your Script logic is proprietary and covers edge cases no app handles
You have an in-house developer or agency relationship
You need full control over the execution logic
Custom Functions are deployed as private Shopify apps and require a Shopify Plus plan.
Not sure which path you're on? Run the Scripts Customizations Report in your Shopify Admin (Settings → Apps → Script Editor). Shopify maps each of your Scripts to a suggested replacement — it's the fastest way to know whether an app covers your use case before you plan a build.
How to Migrate from Shopify Scripts to Functions (Step-by-Step Guide)
Step 1: Audit All Your Active Scripts
Before you migrate from Shopify Scripts to Shopify Functions, you need to know exactly what you're migrating.
Go to Shopify Admin → Settings → Apps and Sales Channels → Script Editor and run the Scripts Customizations Report. This tool lists every active Script on your store — its type, what it does, and Shopify's suggested replacement app for each one. Export it as a CSV.
For each Script, document:
Script type — line item, shipping, or payment
Business logic — what conditions trigger it, what it does to the cart
Source — did you write it, or did a third-party app create it behind the scenes?
Status — is it actively used, or is it a leftover that can be deleted?
Then categorize each Script into one of three paths:
Path
When to use it
Delete
Script is unused or redundant
Replace with an app
Standard discount, shipping, or payment logic — covered by an existing Functions-native app
Build a custom Function
Highly store-specific logic that no app replicates
Note on third-party apps: Some apps programmatically created Scripts on your store without you writing any code. Those Scripts stop working on June 30, 2026 regardless. Contact those vendors now to confirm they've rebuilt on Functions if they haven't, find an alternative before April 15.
Step 2: Audit All Your Active Scripts
Once you've audited, match each Script to its Functions-native replacement. The table below maps script type to the right tool:
Script Type
What It Did
Shopify Functions API
Recommended App
Line item — discounts
BOGO, tiered pricing, free gifts, volume breaks
Discount Functions API
Kite: Discounts & Free Gifts
Line item — bundles
Merge or expand cart line items into bundles
Cart Transform API
Fly: Bundles & Cross Sell / Easy Bundle Builder
Line item — checkout validation
Block checkout based on cart conditions
Cart & Checkout Validation API
Custom Function or Checkout Wiz
Shipping scripts
Hide, rename, reorder shipping rates
Delivery Customization API
Shipzy (formerly Shipfy) / Intuitive Shipping
Payment scripts
Hide, rename, reorder payment gateways
Payment Customization API
HidePay / PayMix
If your Scripts contain complex stacking logic i.e. multiple discounts applying to the same line item; read the stacking section before choosing a path. That behavior works differently in Functions and requires a deliberate decision. You need not worry about this when using an app like Kite Discount & Free Gift as discount stacking is built into the solution.
Step 3: Build or Configure Your Function
If you're using an app: Install it, configure it to replicate your Script's logic, and test it against your documented Script behavior before touching anything live.
If you're building a custom Function (share this with your developer) :
No runtime network calls — if your Script pulled from an external pricing source or loyalty platform, that data must now be pre-synced to Shopify metafields. The Function reads from metafields, not from an external API.
Define your input query — in src/run.graphql, specify exactly what cart data your Function needs. Functions only receive what you ask for.
Test locally first — shopify app function run --input ./tests/mock-cart.json
USE AN APP INSTEAD: Remember, configuring your own Shopify function can be intitmidating. Instead use an that already uses Shopify Functions.
Step 4: Test in Staging — Run Scripts and Functions in Parallel
Don't cut over cold. The safest approach is to run your new Function alongside the existing Script for 2+ weeks before going live.
How to do it without disrupting live customers:
Deploy your Function with a condition for example, only apply it to customers tagged functions-test
Tag a small group of internal or test customers with that tag
Route them through checkout and verify the Function produces identical results to the Script
Test edge cases: empty cart, 50+ line items, stacked promotions, international orders, discount codes applied simultaneously
One caveat: Scripts and Functions don't always coexist cleanly. There are documented cases where an active Discount Function causes Scripts to fail with a nil conversion error. If you see unexpected Script failures during this window, that's why isolate by script type and test each replacement independently.
Code snippet from Shopify function
Step 5: Go Live, Unpublish Your Scripts, and Monitor
Once parallel testing is solid:
Remove the test condition from your Function; deploy the final version with shopify app deploy
Manually unpublish each Script in the Script Editor; do this one by one, not all at once
Verify each Script shows as inactive before unpublishing the next
Monitor for 7+ days post-cutover: conversion rate, AOV, checkout error rate, cart abandonment
Do this before June 30, 2026. Don't wait for the shutdown to do it for you. Scripts disabled by Shopify on June 30 cannot be re-enabled. There is no rollback.
Benefits of Migrating to Shopify Functions
1. Improved Discounts Experience
Dynamic Discounting: Implement advanced discount logic that adjusts discounts based on factors like items, weight, customer loyalty, cart value, or purchase history.
Automated Promotions: Set up functions to automatically apply the best possible promotion based on the customer’s cart composition and past behavior.
Real-time Price Adjustments: Functions can calculate discounts in real-time, providing immediate feedback to customers about available savings, enhancing their shopping experience.
Customer Qualifier Options
Cart Qualifier Options
2. Improved Checkout Experience
Speed Optimization: Functions help streamline the checkout process by executing logic on the server side, reducing the load on the client side and accelerating page load times.
Custom Checkout Flows: Merchants can tailor the checkout experience to different customer segments. For example, repeat customers might see a faster checkout option.
Integrated Payment Solutions: Easily integrate diverse payment gateways and methods that can adapt dynamically based on the customer’s location and preferences.
Functions empower merchants to create faster, smoother checkout processes. For example, you can implement advanced discount applications that calculate dynamically based on customer behavior or cart value, delivering a superior user experience.
5. Scalability and Flexibility
Unlike Scripts, Functions can handle high-traffic scenarios without compromising performance. They also integrate effortlessly with Shopify’s GraphQL APIs, enabling complex customizations with ease.
Extra Information: What Were the Different Types of Shopify Scripts?
1. Line Item Scripts (Pricing and Discounts)
These targeted cart contents, extending far beyond basic discounts to sophisticated pricing adjustments. Common examples:
Progressive discounts by quantity or value (e.g., 10% off 2 items, 20% off 4+).
Bundle deals or "buy more, save more" promotions (e.g., shirt + pants at a set price).
Tag-driven pricing (e.g., reduced rates for wholesale accounts or loyalty members).
Dynamic freebies, where gifts are added and only specific quantities discounted (via line manipulation).
In essence, these acted as the intelligent core for promotional pricing on stores needing flexibility beyond Shopify's standard tools.
2. Shipping Scripts (Delivery Customization)
These managed shipping visibility, labeling, and occasionally pricing based on order context. Typical scenarios:
Conditional method display (e.g., express only for fragile goods or orders over $200).
Group-specific options (e.g., flat rates for retail vs. varied tiers for business buyers).
Geo-fencing rules (e.g., no international for certain items, local pickup in key areas, threshold-based free delivery).
Intelligent defaults, like auto-selecting optimal rates per cart composition.
This transformed rigid shipping setups into responsive, customer-centric offers.
3. Payment Scripts (Gateway Control)
These influenced which payments appeared and their sequence, often tied to business or risk factors. Key uses:
Restrict methods by value or zone (e.g., no cash on delivery for large orders).
Exclusive access (e.g., net-30 terms just for approved B2B tags).
Prioritization to favor high-margin or preferred options (e.g., cards first, then digital wallets).
They provided strategic oversight of the payment stage.
4. Cart Validation and Safeguards
Not a formal category but widely applied, these enforced rules to prevent issues. Examples:
Block incompatible mixes (e.g., age-restricted items without verification).
Mandate minimums before proceeding.
Halt restricted shipments (e.g., hazardous goods to off-limits areas).
These served as operational safety nets alongside revenue tools.
Hurrify customers to buy within a given timeframe with a sales countdown timer & improve conversions
Another popular Shopify checkout app is Checkout Promotions. The app comes with the ability to leverage a collection of highly robust visibility rules that help show customers one-click post purchase upsell promotions after an order payment has been made. Some of its key features include:
Features
AI recommended and manual recommendations for upselling.
Complete branding control.
Checkout Upsell for increasing AOV.
AI recommended and manual recommendations for upselling.
Pricing
Development
Free
Monthly Plan
$99/ month
Plus Plan
$99/ month
Plus Plan
$99/ month
FAQs
1. What is the deadline for migrating Shopify Scripts?
2. Can Shopify Scripts and Functions coexist during migration?
3. Do I need a developer to migrate Scripts to Functions?
4. Are Shopify Functions exclusive to Shopify Plus?
5. What are the costs involved in transitioning to Shopify Functions?
6. What should I test before switching to Shopify Functions?
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Neetika M
Neetika is the founder of Skai Lama. Passionate about building SaaS, Product Development, and Marketing, she talks about eCommerce Growth, Product Bundling, Gifting, Retention, and Shopify.
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