Shopify Script Editor / line item scripts not applying after Plus change or Functions migration — Scripts vs Shopify Functions, checkout extensibility.

Several products can look like “checkout discounts / shipping / payment rules vanished.” They do not share a settings panel. This page is only when Script Editor Line Item, Shipping, or Payment Scripts that used to apply stopped changing cart or checkout after a Plus plan change, Checkout Extensibility upgrade, or Functions migration. A planned inventory-and-map job (list every Script → pick a Function API → publish) is shopify-scripts-to-functions-migration. A Shopify Function automatic discount that never changes the line total is shopify-functions-discount-not-applying. Quantity breaks / Buy X Get Y UI on PDP or cart is shopify-quantity-breaks-not-showing. Checkout UI extension / app blocks missing on checkout are shopify-checkout-ui-extension-not-loading. This page is only: Script Editor scripts not applying after Plus change or Functions / extensibility cutover.

Six ordinary reasons Scripts stop applying: Script unpublished or draft after an edit, Plus Script Editor access lost after a plan downgrade or shop transfer, Checkout Extensibility / checkout customization disabled Ruby Scripts on the Live profile, Scripts uninstalled during a Functions migration while the Function was never published on the live shop, wrong surface (you are testing typed discount codes / Functions discount math / quantity-break theme blocks / checkout UI extension placement), or checkout.liquid retirement left Additional Scripts / thank-you scripts elsewhere — that last path is checkout-extensibility-upgrade-broken or thank-you-page-upsell-broken, not this page. Walk the Script Editor + Live profile path first. You already pay for Plus and Script Editor / Functions. You do not need another checkout-rules SaaS to read publish state.

On the live Plus shop (not a development store copy), open Apps → Script Editor. For each Line Item / Shipping / Payment Script that used to apply, note Published vs Draft, last edited date, and whether the Script still exists after a shop transfer or Plus change. Then open Settings → Checkout and accounts → Checkout customization (or Checkout Extensibility upgrade status). Note whether the Live profile is on extensible checkout and whether Shopify still runs Script Editor Scripts on that profile.

Honest proof: screenshot Script Editor publish badges, the Live checkout profile name, and — if Scripts are disabled by extensibility — the Shopify Functions / app discount list showing whether a replacement Function is installed and active on this shop. If Script Editor is missing entirely after a plan change, document plan eligibility before rewriting discount apps. If the only symptom is a typed discount code rejecting at checkout, switch to discount-code-not-applying instead of republishing Scripts.

If the Script is Draft, Publish it and retest a known cart that used to trigger the rule (gift with purchase threshold, free shipping override, payment method hide). If Plus Script Editor access disappeared after a plan change or transfer, restore Plus eligibility or treat the logic as a Functions migration — do not assume a third-party discount app will recreate Script behavior without mapping. If Checkout Extensibility turned Scripts off on the Live profile, publish the matching Function (cart / product discount, delivery customization, payment customization) on the live shop and prove checkout totals / shipping / payment methods match the old Script before unpublishing anything else.

Honest proof: one checkout session where the old Script behavior is visible again — either Script Published and applying on a profile that still runs Scripts, or the Function installed on Live with matching line / shipping / payment outcome. Checkout UI extension placement stays on shopify-checkout-ui-extension-not-loading. Quantity-break theme blocks stay on shopify-quantity-breaks-not-showing. Keep those panels off this Script Editor cutover path.

Script Editor Ruby Scripts (Line Item, Shipping, Payment) run on Plus checkout only while the shop still allows them. Shopify Functions replace that logic as cart / product / order / shipping / payment customization extensions. Checkout Extensibility moves thank-you / order status / checkout UI away from checkout.liquid — that is a different surface from Script Editor price rules. If you need a full inventory → map → publish project, use shopify-scripts-to-functions-migration. This page is the emergency when behavior that already worked stopped after Plus / extensibility / cutover — not the planned migration checklist.

Do not run Scripts and the replacement Function both active with overlapping rules unless you intend double discounts. After parity, unpublish the Script. If Functions discount math is wrong but Scripts were never in play, use shopify-functions-discount-not-applying.

Switch pages if any of these is true: no Script Editor Script ever applied and you are debugging a Functions automatic discount (functions discount), a typed discount code rejects (discount code), quantity / volume UI missing on PDP (quantity breaks), checkout UI extension / app block missing (checkout UI extension), or thank-you / order status after checkout.liquid retirement (checkout extensibility upgrade). Stay here only when Script Editor logic that used to apply stopped after Plus / Functions / extensibility.

Stay DIY if you can spend one afternoon on the list above: prove Script Editor publish state on the live Plus shop, confirm Plus eligibility after any plan change, check whether Checkout Extensibility disabled Scripts on the Live profile, publish the matching Function if Scripts were cut over, and stop confusing Functions discount math / quantity-break UI / typed codes / checkout UI extensions with this Script Editor cutover path. That is the whole playbook. No agency required. Short answers also live on the merchant FAQ. Related pages: Scripts → Functions migration, Functions discount not applying, quantity breaks, checkout UI extension not loading.

Pay for help when the work is not republishing one Script — it is connecting the stack you already have so lead capture is not dying in DMs, checkout and ops exceptions land in a channel you already check, and the live store is one workflow instead of a spreadsheet plus a Slack bot you forgot. That is the Latch AI Ops install.

What $997 USD one-time buys: lead capture on the live store, ops alerts in a channel you already check, and a checkout-ready workflow. 72 hours after collaborator access, not after payment. One live Shopify store. Access plus a delivery thread. Store URL collected at checkout. Not a SaaS seat, not a Scripts agency retainer, not a conversion guarantee, not a brand or theme job.

Other shops' public ranges, not testimonials: a checkout / ops install typically runs $500–$2,500. A full ops consulting block typically runs $2,000–$5,000. $997 is the cheap end of that work, sold as a 72-hour install of three systems — not as an earnings number or conversion-lift claim.

What it does not buy: more orders, recovered revenue, a forever Script Editor uptime guarantee, a custom Functions rewrite retainer, or a case study. Latch AI Ops has not published customer proof because there are no customers yet. You are buying the install.

Checkout is on Whop. Operator is Nico. United States offer. You can revoke collaborator access after handoff. We do not take owner passwords.