Scripts Migration

Migrating Shopify Scripts to Shopify Functions

Shopify Scripts have been retired in favor of WebAssembly-based Shopify Functions. Any custom checkout logic — custom discounts, shipping rules, line item modifications — now runs natively through Functions. If your store still has unmigrated Scripts or legacy checkout logic, transitioning to Functions restores native reliability and performance.

Book a Diagnostic Audit →
What breaks

What checkout features are impacted when Scripts are retired?

Shopify Scripts was a Ruby-based execution layer that ran custom logic at checkout. With Functions replacing Scripts, unmigrated Ruby code simply doesn't execute.

  • Custom discount logic

    Percentage-off, fixed-amount, and buy-X-get-Y discounts built in legacy Scripts stop executing. Storefront prices revert to Shopify's default pricing. The discounted price simply doesn't apply.

  • Volume / tiered pricing

    Quantity-based pricing (e.g. '10+ units at 15% off') built on legacy Scripts stops working. Customers pay standard price regardless of quantity.

  • Customer-specific pricing

    B2B or wholesale pricing that uses customer tags to apply Scripts-based discounts stops executing. All tagged customers revert to retail pricing at checkout.

  • Checkout bundling rules

    Multi-product bundle discounts, free gift logic, and spend-threshold rewards built via Scripts stop executing. Applications fall through to no discount at checkout.

  • Shipping rate modifications

    Custom shipping rate logic, free shipping thresholds, rate blending, carrier overrides, built in Scripts stops executing. Customers see unmodified carrier rates.

If your store relies on legacy checkout logic, migrating to Shopify Functions ensures your pricing and shipping rules run reliably on Shopify's native infrastructure.

The approach

Do all Shopify Scripts need to be replaced with Shopify Functions?

Before writing a single line of Functions code, I triage every Script in your store. A lot of them can be replaced by Shopify's own native Automatic Discounts, Quantity Rules, or Catalogs features, no development required. Identifying those first reduces the scope and cost of the migration before any pricing conversation happens.

Every Script gets assigned one of three outcomes: native replace, Functions build, or remove. That triage report is the first deliverable of a Scripts Audit.

NATIVE REPLACE

Many Scripts can be replaced entirely by Shopify's own Automatic Discounts, Quantity Rules, or B2B Catalogs features, no development required. If your Script falls into this category, I document the native configuration and you implement it directly in the Shopify admin. No Functions code needed.

FUNCTIONS BUILD

Scripts with logic that has no native equivalent, complex tiering, multi-condition rules, cross-product interactions, require a Checkout Functions rebuild in Rust/WASM. This is where the technical migration work happens. Scoped, tested, and deployed through a Custom App.

REMOVE

Some Scripts are ghost code. They were installed for a campaign or test years ago and are no longer used. The triage identifies these. Removing dead Scripts reduces checkout complexity with zero rebuild work.

Three options

How do I migrate my Shopify Scripts to Shopify Functions?

Self-Serve Playbook

$295 / $795 / $995

Three tiers, one-time digital download

  • Self-Serve: $295. Triage framework + migration guide
  • Hybrid: $795. Adds reviewed code templates + test protocol
  • Agency License: $995. Full commercial use + team distribution rights

A 14-chapter, 70-page technical guide covering the complete Scripts-to-Functions migration. Includes the triage framework, production-ready code templates, testing protocols, and deployment checklists. Built for engineers and technical operators who want to run the migration themselves.

100% of the purchase price is credited toward a Diagnostic Audit.

Get the Playbook →
Scripts Triage Report

$500

Fixed price, credited toward Done-for-You Migration

  • Scripts replaced by Shopify's native discount or shipping features, no dev work required
  • Scripts that require a Functions rebuild, classified by complexity with timeline estimates
  • Scripts safe to deprecate with no replacement needed

Every Script in your store classified by migration path. You get a prioritized action list so you know exactly what needs to happen — and what doesn't. Turnaround: 3 business days.

Get the Triage Report →
Done-for-You Migration

$2,500–$8,000

Migration scope and timeline are determined from the Triage Report

I triage your Scripts, identify which require Functions rebuilds, and complete the migration. Fixed-scope engagement: one revision cycle, typically 5–15 days depending on Script complexity. Includes the triage report, all Functions code, a Custom App deployment, and a written walkthrough of every change.

$500 Triage Report fee is credited in full toward this engagement.

Start your migration →

Ready to transition from Scripts to Functions?

If you're not sure which path fits your store, start with the Playbook. The triage framework in Chapter 2 tells you exactly what you're dealing with. If the audit confirms you need the done-for-you migration, 100% of the Playbook price is credited toward the Diagnostic Audit, so it's not a sunk cost.

Get the Playbook →