Shopify Functions / Checkout UI / automatic discount app not applying at checkout — Functions API, discount combinations, Plus vs non-Plus.

Several products can look like “my discount never lands at checkout.” They do not share a settings panel. This page is only when a Shopify Function, Checkout UI extension, or automatic discount app should apply a line at checkout and never does — no automatic amount, empty discount summary, or Function that returns no targets. A shopper typing a code that rejects is discount code not applying. Blank B2B / Plus company catalog prices is B2B catalog not showing. Missing Shop Pay / accelerated checkout button is Shop Pay not showing. Card declined / AVS / 3DS is Shopify Payments card declined. This page is only: Functions / Checkout UI / automatic discount app not applying at checkout.

Six ordinary reasons automatic Functions discounts stay blank: Function extension not published on the live shop, app installed only on a development / Plus test shop, discount combinations blocking automatic + code stacks, cart failing Function eligibility (collection / customer / market), Plus vs non-Plus Checkout Extensibility limits, or you are debugging typed codes / B2B catalog / Shop Pay / card declines instead. Walk them in that order. You already pay for Shopify. You do not need another seat to republish a Function and read combination rules.

Settings → Apps and sales channels (or Apps): open the discount / Functions app. Confirm it is installed on this shop — not only a partner dashboard / development store. Inside the app (or Shopify CLI / Partners → Extensions): the discount Function and any Checkout UI extension must be published / released to the live shop. A draft Function that only runs in a preview session will look “built” while live checkout never sees it.

Honest proof: place a qualifying cart on the live storefront, open checkout in Incognito, and confirm whether an automatic discount line appears before you type any code. If a typed code rejects but automatic lines are out of scope, leave for discount code not applying. Do not mix those proofs.

Automatic Functions discounts still sit inside Shopify’s discount combination model. A product discount Function that cannot combine with order / shipping discounts will silently lose when another discount already owns the cart. Minimum purchase, customer segment, market, and collection targeting inside the Function (or the automatic discount configuration) can also return zero targets even when the app “looks on.”

Fix: Discounts → open competing automatic and code discounts → Combinations. Temporarily turn off other automatic discounts and retest a bare qualifying cart. Confirm the Function’s cart inputs (collections, tags, customer tags, markets) match the test cart. If the only failure is a shopper-entered code, leave for discount code not applying.

Shopify Functions and Checkout Extensibility surface area differ by plan. A discount Function or Checkout UI extension that works on a Plus development / sandbox shop can no-op or be unavailable on a non-Plus live shop. Checkout UI that assumes Plus-only APIs can render a banner while the discount Function never runs. Partner docs and app listings often bury the plan requirement.

Fix: confirm the live shop’s plan and the app’s plan requirements. If you tested on Plus and went live on non-Plus (or the reverse), re-read the Function / Checkout UI docs for that plan. B2B catalog blank for company buyers is a different product — leave for B2B catalog not showing.

Checkout UI and discount Functions are separate extensions. Merchants often see a custom block / banner (Checkout UI) and assume the discount Function is live — while the Function still returns empty targets, is unpublished, or is blocked by combinations. UI without a discount line is still this page’s product.

Fix: Partners / app → list extensions → confirm both Checkout UI and the discount Function are published to the live shop. Retest checkout looking specifically for the discount summary line / reduced total — not only the custom banner. If Shop Pay / accelerated checkout is missing entirely, leave for Shop Pay not showing. If the card declines after a discount does apply, leave for Shopify Payments card declined.

A shopper-entered code that rejects is discount code not applying. B2B / Plus company catalog prices or products blank for logged-in buyers is B2B catalog not showing. Shop Pay / accelerated checkout button missing is Shop Pay not showing. Card declined / AVS / 3DS / fraud filters is Shopify Payments card declined.

The only honest test for this page: a qualifying cart on the live shop never receives the automatic / Functions discount at checkout — prove Function published, prove combinations / eligibility, prove Plus vs non-Plus surface area, prove Checkout UI is not standing in for a missing Function, hard-refresh. Anything else is a different product.

Stay DIY if you can spend one afternoon on the list above: republish the discount Function on the live shop, clear combination fights, match cart eligibility, confirm Plus vs non-Plus limits, and stop confusing typed codes / B2B catalog / Shop Pay / card declines with a silent automatic discount. That is the whole playbook. No agency required. Short answers also live on the merchant FAQ. Related pages: discount code not applying, B2B catalog not showing, Shop Pay not showing, Shopify Payments card declined.

Pay for help when the work is not the Function publish toggle — it is connecting the stack you already have so lead capture is not dying in DMs, storefront and checkout-ready 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 theme rebuild 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 Functions-discount-proof theme guarantee, 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.