# Try a rule on your live store with test mode

FunctionFlow AI · Test & publish · Updated October 3, 2026

> Publish a function for customers tagged ff-test only, check it in your real checkout with your real products, then go live for everyone in one click.

Test mode publishes a function to your live store but shows it **only to customers tagged `ff-test`**. Everyone else checks out as if the function didn’t exist. It’s the safest way to check a rule with your real products, shipping rates and payment methods before customers see it.

## Publish in test mode

When you publish a function for the first time, FunctionFlow asks how it should go live:

![The publish dialog with Test mode first selected](https://help.fleekapps.com/media/functionflow-ai/publish-dialog.webp "Test mode first is selected by default.")

Choose **Test mode first** and click **Publish in test mode**.

You can also switch test mode on or off any time with the switch in the **Test mode** card in the builder’s sidebar.

![The Test mode card](https://help.fleekapps.com/media/functionflow-ai/test-mode.webp "The Test mode card in the builder sidebar.")

## Check it in your checkout

1. In Shopify admin, open **Customers**, find your own customer account (or create one) and add the tag `ff-test`.
2. In your online store, **log in** with that account. Guests never see functions in test mode.
3. Build a cart that should trigger the rule and go to checkout. The discount, hidden method or message should appear.
4. Log out, or use a private window, and check out again: you should see your normal checkout.

Tags aren’t case-sensitive, so `FF-TEST` works too.

## Go live for everyone

When you’re happy, open the function. The **Test mode** card says *Live for tagged customers only.* — click **Go live for everyone** and confirm. The function now runs for every customer, straight away. No new version is created: the version you tested is the one that goes live.

To go back to test mode later, turn the switch on again. On a live function, customers without the tag stop seeing it right away.

## Things to know

- Test mode works for every kind of builder function: discounts, shipping, payment and checkout rules. Functions written in the code editor don’t have test mode.
- A function in test mode is active in Shopify, so it counts toward Shopify’s limit of 25 per kind. Customers without the tag can still enter a discount code, but it won’t give them a discount.
- Test mode uses one of the 100 customer tags a function can check. If a rule already uses 100, remove one to turn test mode on.
- The [tester](https://help.fleekapps.com/functionflow-ai/test-a-function/) simulates test mode too: add `ff-test` to the customer’s tags to see the rule apply.
- Remember to remove the `ff-test` tag from customers who shouldn’t keep seeing test functions.

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Source: https://help.fleekapps.com/functionflow-ai/test-mode/