Shopify Functions vs Shopify Scripts: What B2B Developers Must Migrate Before End 2026

If your Shopify Plus store still runs checkout logic through Shopify Scripts, the clock is louder than it sounds. Shopify has confirmed that Scripts stop executing entirely on Aug 31, 2026. Editing and publishing new Scripts already stopped on April 15, 2026. There’s no extension coming this time – Shopify pushed this deadline twice before, and it has now said publicly that Aug 31 is the hard stop. 

For a B2C store running a simple free-shipping script, that’s an inconvenience. For a B2B operation running custom pricing tiers, quantity breaks, net-payment terms, and customer-tag-based checkout rules, it’s a revenue risk. This is the migration guide for developers and merchants who need to move from Scripts to Shopify Functions and build more flexible B2B ecommerce solutions before it becomes an emergency.  

Why Shopify Is Retiring Scripts 

Shopify Scripts were built on Ruby, running inside Shopify’s legacy checkout. They were never designed to scale with the platform’s move to extensible, composable checkout. Shopify’s own changelog puts it plainly: Scripts can’t evolve to meet modern extensibility needs without a full rewrite of their runtime, so Shopify chose to build a new system instead of patching the old one. 

That new system is Shopify Functions – compiled WebAssembly modules that run inside Shopify’s core infrastructure at defined points in the commerce lifecycle, rather than as an add-on script layer bolted onto checkout. 

Shopify Functions vs Shopify Scripts: The Core Differences

The practical shift for developers is the deployment model. Functions live inside a version-controlled app, not a text box in Shopify admin. That’s a better architecture, but it also means B2B logic needs to be re-engineered, not just copy-pasted. 

What B2B Merchants Stand to Lose If They Wait 

Custom Discount and Pricing Logic 

Wholesale tiers, quantity-based pricing, and customer-group discounts frequently live inside Scripts because they need conditional logic Shopify’s native discount engine didn’t originally support. When Scripts stop executing, those discounts don’t degrade gracefully – they simply disappear from checkout on July 1. 

B2B Payment and Shipping Rules 

Many B2B stores hide payment methods for certain customer tags, gate purchase orders and net-terms behind approval logic, or apply freight rules based on order weight and destination. All of this typically runs through Script Editor. Once execution stops, that gating logic goes with it, which means unapproved buyers could suddenly see payment options they were never meant to access. 

This isn’t hypothetical. Guides for migrating away from deprecated flag stores that use Scripts for custom discounts, B2B pricing, shipping rules, or payment controls highlight these as the riskiest because it’s tough to rebuild that logic quickly when you are up against a deadline. 

Migration Timeline: What to Do Before Aug 31, 2026 

Step 1 — Audit Every Active Script 

Pull Shopify’s Scripts Customizations Report first. It tells you exactly which scripts are live and what they touch, so you start from an inventory instead of a guess. 

Step 2 — Prioritise by Risk 

Not every script needs a custom Function. Sort them into three buckets: scripts you can retire outright, scripts a public app from the Shopify App Store can replace in days, and high-risk scripts usually B2B pricing or payment gating that need a purpose-built Function. 

Step 3 — Build, Test, Cut Over in Waves 

Migration guides tracking real-world projects put a mid-complexity Functions build at roughly 8 to 14 weeks, covering scoping, development, staging tests, and production cutover. Larger catalogs with hundreds of promotional rules take longer and should move in batches rather than one big-bang release. Test every rule on a development store before it touches live checkout Functions and Scripts can run side by side until the deadline, so there’s no need to flip everything at once. 

Why This Extends Beyond Checkout 

This deadline is really a forcing function for a broader question: is your storefront architecture still fit for how B2B buyers actually shop in 2026?McKinsey’s Global B2B Pulse research shows that 39% of B2B buyers now make orders over $500,000 using self-service ecommerce or remote methods. That’s up from 28% just two years ago. Also, Gartner’s buyer survey found that 67% of B2B buyers now prefer to buy without talking to a salesperson. 

That shift puts real pressure on the storefront itself. Slow checkout logic, broken pricing rules, or a dated interface don’t just cost conversions – they push high-value buyers back toward a sales rep they were trying to avoid. This is where the Functions migration and a broader Shopify website design refresh tend to happen together. Teams already touching checkout infrastructure use the moment to modernise navigation, account portals, and quote workflows at the same time, rather than treating it as two separate projects a year apart. 

Choosing a Shopify Plus Development Company for the Migration 

Rebuilding checkout logic under a fixed deadline isn’t a good candidate for trial and error. A specialised eCommerce website development company brings three things an in-house team often can’t staff up for in time: hands-on experience shipping Functions in Rust or JavaScript, familiarity with B2B-specific extensibility points like payment and delivery customizations, and a QA process built around checkout-critical code. 

For merchants running complex B2B logic – tiered contract pricing, multi-entity accounts, approval workflows – this is also the right moment to evaluate the broader storefront, not just the checkout layer. A partner experienced in B2B ecommerce website development can fold the Scripts migration into a wider audit covering catalog structure, self-service account tools, and site performance, so the June 30 deadline becomes a platform upgrade instead of a patch job. 

Frequently Asked Questions 

Will my store break the moment Scripts stop working? Not instantly, but any logic running through Scripts discounts, shipping rules, payment gating stops applying the moment execution ends on June 30, 2026. For B2B stores, that often means pricing reverts to defaults and gated payment methods become visible to everyone. 

Can Shopify Functions and Scripts run at the same time? Yes. Shopify has confirmed both can operate in the same store until the deadline, which is what makes a phased, wave-based migration possible instead of a single risky cutover. 

Will Shopify migrate my Scripts automatically? No. Shopify provides the Scripts Customizations Report and recommended apps, but every script needs to be manually reviewed, rebuilt, and tested by your team or your development partner. 

How long does a typical migration take? Industry benchmarks put a focused migration of 5 to 15 scripts at 8 to 14 weeks, including scoping, development, staging tests, and production rollout. Complex B2B pricing and payment logic sits at the longer end of that range.