Add the Rules Executor to your checkout
In short
Checkout Ninja's rules run inside an app block called Rules Executor. Open Shopify's checkout editor, click Add app block, choose Rules Executor and save. If any rule shows an error message, also allow the block to block checkout progress, or Shopify lets buyers continue anyway.
✓ Applies to
- Deluxe plan only (checkout rules aren't included in Advanced)
- Shopify Plus stores (and development stores for testing)
- Every rule action: Hide payment method, Show Error Message, Modify Cart and Validate Via API
✕ Doesn't apply to
- Custom Blocks. Those are placed with the Custom Block app block and a Block ID
- The thank-you and order status pages
Before you start
- Create at least one rule under Rules in Checkout Ninja and set its Status to Active. New rules start as Draft, and the Rules Executor ignores drafts.
- Shopify Plus, or a development store. Checkout app blocks in the information, shipping and payment steps are a Shopify Plus feature.
Steps
- In Checkout Ninja, open Rules. The Setup Guide card links to your checkout editor. Click it, or go to Settings → Checkout → Customize in your Shopify admin.
- In the checkout editor, click Add app block in the checkout section where your rules should run.
- Choose Rules Executor. It has no settings to fill in.
- If any of your rules use Show Error Message or Validate Via API, open the block’s settings in the checkout editor and allow it to block checkout progress. See the note below.
- Click Save in the checkout editor.
Shopify decides whether an app may stop a buyer from continuing. The Rules Executor asks for that permission, but the merchant has to grant it for each app block in the checkout editor. Without it, Shopify ignores the block request and buyers can continue past your error rules. Fix an error that doesn’t block checkout.
Where to put it
The block renders nothing except a brief spinner, so its position doesn’t matter visually. What matters is that it’s on the page where your rule’s conditions can be evaluated:
- One-page checkout: anywhere in the checkout body.
- Three-page checkout: place it on the step where the buyer has already entered what your conditions check, or on a later step. For example, a rule that checks the shipping country needs the executor on a step after the address is entered.
Verify it worked
- Create a simple test rule: a Cart Total condition that your test cart matches, with a Show Error Message action at Top of the checkout. Set it to Active and save.
- Open your store, add products to the cart and go to checkout. Try to continue. The error appears and you can’t move forward.
- Change the cart so the condition no longer matches, for example remove a product. You can now continue.
- Set the test rule back to Draft when you’re done.
Limitations
- Shopify Plus only for the information, shipping and payment steps. That’s a Shopify rule for all checkout apps.
- The executor loads your rules when the checkout opens. It reads 10 rules from your store, drafts included, and then drops the drafts. If you have more than 10 rules, some active rules may not load. Delete rules you no longer need.
- A rule with no conditions always applies.
- While the executor is evaluating rules, it holds checkout progress for that moment, if you’ve allowed it to block progress.
Troubleshooting
Rules Executor isn’t in the Add app block list. Make sure you’re editing the checkout page in the checkout editor, not the thank-you or order status page. The block only targets the checkout.
The block is added but rules still do nothing. Check that each rule’s Status is Active and that you clicked Save in the checkout editor. Then test with a cart that matches the rule’s conditions. Full checklist.
Buyers can continue even though an error rule matches. The block isn’t allowed to block checkout progress. Turn that on in the block’s settings in the checkout editor and save.
Frequently asked
The app says 'Rule Executor'. Is that the same block? +
Yes. The setup text in the app calls it Rule Executor, but in Shopify's checkout editor the app block is named Rules Executor. Pick that one.
Do I need one Rules Executor per rule? +
No. One Rules Executor loads your active rules and runs them all. You don't paste an ID into it, and it has no settings of its own.
Will buyers see the Rules Executor block? +
Only briefly. It shows a loading spinner while it evaluates your rules and nothing otherwise. Anything buyers see, such as an error message or a hidden payment method, comes from the rule's actions.
Do rules work on non-Plus stores? +
The Rules Executor is a checkout app block, and Shopify only allows those in the information, shipping and payment steps on Shopify Plus. Development stores can use it for testing.