Shopify Scripts to Functions Migration: Complete Guide (June 2026 Deadline)

TL;DR

• Shopify Scripts deprecated — must migrate to Functions by June 2026
• Functions execute faster and have better parity with Shopify's backend
• Migration is not automatic — requires code rewrite from Ruby to JavaScript/TypeScript
• New API capabilities in Functions that Scripts couldn't access
• Start now — June deadline is closer than it looks

The Deadline: June 2026

Shopify announced in Winter '26 Edition that Scripts will be fully deprecated by June 2026. After that date, Script-based checkout customizations will stop working.

Scripts vs Functions: Key Differences

Functions now run on WebAssembly (edge, sub-5ms execution) vs Scripts running on Shopify's legacy infrastructure. Functions use JavaScript/TypeScript instead of Ruby, and have access to the full GraphQL Admin API with AI integration capabilities.

Migration Strategy

1. Inventory your Scripts — Find all Scripts in store using Shopify CLI or Admin.

2. Choose Function Type — Product discounts, order discounts, shipping discounts, payment customizations, or delivery customizations.

3. Rewrite Logic — Convert Ruby → TypeScript. Key change: direct mutation becomes return output object.

Common Migration Challenges

Metafield Access: Scripts could read metafields directly. Functions require GraphQL input queries.
External API Calls: Neither Scripts nor Functions support this (WebAssembly sandbox). Use Shopify Flow + app backend.
Complex Logic: Some Script logic doesn't map 1:1. Solution: Combine multiple Functions or use Payment/Delivery customizations.

Timeline Recommendation

March 2026: Inventory all Scripts, prioritize critical ones
April 2026: Migrate high-priority Scripts to Functions
May 2026: Migrate remaining Scripts, full testing
June 2026: Scripts deprecated — must be on Functions

Bottom Line

Migration is mandatory, not optional. The good news: Functions are more powerful, faster, and future-proof. The bad news: you have 3 months left. Start with your most critical discount Script. Get one migration under your belt before tackling the rest.