Troubleshooting

A function isn’t applying at checkout

Work through these in order:

1. Is it published? The status should be Active. A Draft isn’t running; a Scheduled function starts at its start date.
2. Are your changes published? If it shows Unpublished changes, checkout is still running the previous version — click Save & publish.
3. Is it in test mode? With the Test mode badge, only logged-in customers tagged ff-test see it. See Test mode.
4. Do the conditions match this cart? Open the tester, recreate the cart and run it. Why shows which condition failed and what the function saw.
5. Do the names match? Payment and shipping methods are matched by the name shown at checkout. Standard delivery won’t match a rate called Standard Shipping.
6. Is there an address yet? Address conditions only apply once the customer has entered an address.
7. Is it a discount code? Code discounts only apply when the customer enters the code.

Tip: In the tester, Collection, Product and Variant conditions can’t match because sample items aren’t real products. If your rule uses them, check it with test mode on your real store.

Publishing failed

The builder shows The last publish failed with Shopify’s message. Your draft is kept. Common messages:

• “Shopify allows at most 25 active … functions per store. Unpublish one first.” — Shopify’s limit per kind of function. Unpublish or archive one you don’t need. Free and discounted shipping count as discounts.
• “This function is too large (… KB). Shopify limits function configuration to 10 KB — split it into two functions.” — simplify the rule or split it into two functions.
• “Test mode needs one free customer tag slot.” — the rule already checks 100 customer tags. Remove one and try again.
• “Shopify session expired.” — reopen FunctionFlow from Apps in Shopify admin and publish again.
• A message ending in failed: followed by Shopify’s explanation — Shopify rejected the change. The text after failed: says why; email us if it isn’t clear.

A plan message stops me saving or publishing

• “Choose a plan to start creating functions.” — pick a plan on Plans.
• “The … builder isn’t included in your plan.” — this kind of function needs a bigger plan. Existing functions keep running.
• “Your … plan includes N functions.” — archive functions you don’t need (drafts count too) or upgrade.

See Plans and billing.

A scheduled function didn’t start or end on time

• Discounts are started and ended by Shopify at the exact times. Check them under Discounts in Shopify admin; FunctionFlow may still show the status they had when you published.
• Shipping, payment and checkout rules are switched by FunctionFlow. If the function shows Schedule waiting for an admin visit, nobody from your team has used the app recently — open FunctionFlow and it switches straight away.
• Times use your store’s time zone (Shopify admin → Settings → General).

A time-based rule runs at the wrong time

Time conditions use your store’s time zone, not your computer’s. Check it in Shopify admin → Settings → General. Overnight windows such as 10:00 PM to 2:00 AM run across midnight, and each function can have one time window. Test with the Store date & time box in the tester.

A discount doesn’t combine with other discounts

Open the function’s Discount settings and tick the kinds of discount it may combine with — Order discounts, Product discounts, Shipping discounts — then Save & publish. The other discount must also allow combining with this one.

A discount still applies to sale items

Open the discount action, tick Exclude items already on sale, then Save & publish. An item is on sale when its compare-at price is higher than its price.

A gift isn’t discounted

Shopify Functions can’t add products to the cart. The gift is discounted once the customer adds it — make sure the gift products are chosen in the tier and that the cart reaches the tier.

A payment or shipping method wasn’t hidden

Check the method’s exact name at checkout, and that the rule uses Name contains with a part of that name. Run the tester with the same name in Payment methods at checkout or Shipping rates at checkout.

The AI generator stopped working

• “You’ve reached the hourly AI limit.” — each store can generate 30 times an hour. Try again later.
• “The AI could not produce a valid function for that request.” — rephrase it more simply, or start from a template.

The app won’t open or says the session expired

Open FunctionFlow from Apps in your Shopify admin. If a page shows Your session expired. Please try again., reload it from there.

Still stuck?

Email us with your store’s .myshopify.com address, the function’s name and what you expected to happen — see Support.