On June 30, 2026, Shopify Scripts stopped running. Every line item, shipping and payment script went dark that day. Stores that migrated to Shopify Functions kept their discounts and shipping rules. Stores that did not are often still losing orders without knowing it, because a dead Script throws no error your customer sees.
If your store or your clients’ stores used Scripts, this is how to check what broke, what it costs, and how to rebuild it properly.
What actually stops working
Scripts are the bits of Ruby that run in your checkout through the Script Editor app. Three kinds, all retiring together:
Line item scripts. Cart and product discounts, tiered pricing, buy-one-get-one logic.
Shipping scripts. Hiding, renaming, or reordering shipping rates, and free shipping thresholds.
Payment scripts. Hiding or sorting payment methods by cart, customer, or total.
If you are on Shopify Plus, this followed the bigger checkout change that landed on August 28, 2025, when checkout.liquid, the old Thank-you and Order-status customizations and script_tags in checkout were retired. Scripts were the last piece standing, and June 30 closed it.
The four places this costs you orders
A dead Script does not throw an error your customer sees. It just stops applying. That is the dangerous part, because the leak is silent.
Promised discounts vanish. The 15 percent tier your ads promise stops applying at checkout. Customers hit a higher total than they expected and abandon. Your ad spend already paid for that click.
Shipping logic resets. Free shipping over a threshold disappears, or rates you hid come back. Surprise shipping cost is the single most common reason carts get abandoned.
Payment options scramble. Methods you carefully ordered or hid reappear, adding friction at the exact moment of decision.
Upsell and bundle math fails. Any cart logic stacked on Scripts stops calculating, so the AOV plays you built quietly stop earning.
Every one of these sits at the bottom of the funnel, where the traffic is most expensive and the intent is highest. It is the worst place to spring a leak.
Functions and Checkout Extensibility, in plain terms
The replacement is not a like-for-like swap, and that trips people up. Scripts were one tool. The new model splits the work into three:
Shopify Functions handle the logic: discounts, shipping rate rules, payment customizations. They run faster than Scripts and are version-controlled, but they are built and deployed differently, not edited in a box in the admin.
Checkout UI extensions handle what the customer sees: banners, custom fields, upsells, and trust content in the checkout.
The Branding API handles the look.
The upside is real. Functions are quicker and more stable, and the new checkout is harder to slow down with third-party scripts. The catch is that anything custom has to be rebuilt deliberately, not ported line for line.
How to migrate without losing the conversion logic
The mistake we keep seeing is treating the migration as an IT task. A developer rebuilds the rules so they technically work, nobody checks whether they still convert, and a working discount comes back slightly wrong.
The order that protects revenue:
Inventory every Script and what it earns. List each one and the money it touches. A free-shipping threshold driving AOV is not the same priority as a cosmetic tweak.
Rebuild the revenue logic first in Functions, starting with discounts and shipping, the two that abandon carts fastest.
Test the cart and checkout end to end before you flip it, on mobile, where most of your traffic and most of your drop-off lives.
Reconcile after launch. Watch conversion rate and AOV for the first weeks and confirm the numbers held, not just that the page loads.
Done in that order, the rebuild is a chance to clean up logic that piled up over years. If you want a second set of eyes, our funnel optimization team does exactly this work.
Check if you are still leaking in ten minutes
Place a test order with your usual discount code and a cart above your free shipping threshold. Check the total, the shipping rate and the payment options against what your ads and emails promise. If anything is off, a Script used to handle it and nothing replaced it.
If you manage client stores, check every one of them, not just the largest. A silent discount failure on a client account is the kind of thing that ends a retainer.
If you would rather not find out the hard way, we will audit your checkout logic for free and tell you exactly what is missing and what it is worth.