# Custom Rules Block orders that don't meet your requirements by creating custom validation rules. Set conditions based on cart value, product quantity, or specific products — and display clear error messages at checkout. {% hint style="success" %} **Available on all Shopify plans.** Custom Rules uses Shopify Functions — no Shopify Plus required. {% endhint %} *** ## What it does Custom Rules lets you create validation rules that block checkout when specific conditions are met: * **Cart total** — require a minimum or maximum order value * **Cart quantity** — limit the total number of items * **Product quantity** — restrict how many of a specific product can be ordered * **Product restrictions** — block checkout when certain products are (or aren't) in the cart Each rule shows a **custom error message** at a position you choose — either as a banner at the top of the page or inline next to a specific field. *** ## Step 1: Go to Checkout Validations In the app sidebar, click **Checkout Validations**. You'll see the list of all validation rules. {% embed url="" %} ### List page overview | Feature | Description | | ----------------- | -------------------------------------------------------- | | **Search** | Find rules by name | | **Status filter** | Filter by Active, Inactive, or Test mode | | **Table** | Shows rule name, status, conditions summary, and actions | | **Actions** | Activate/Deactivate, Edit, Delete for each rule | | **Bulk actions** | Select multiple rules to activate, deactivate, or delete | *** ## Step 2: Create a new rule Click **Create validation** (top right). The editor opens with three sections: General Setting, Trigger Conditions, and Error Message. {% embed url="" %} *** ## Step 3: Set name and status | Setting | Description | | ------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------ | | **Rule name** | A descriptive name for your reference (e.g., "Minimum order $50") | | **Status** | **Active** — rule applies at checkout. **Test mode** — only triggers when checkout email is `aov@testing.com`. **Inactive** — rule is saved but not applied. | {% hint style="info" %} **Tip:** Start with **Test mode** to verify the rule works correctly before activating it for all customers. {% endhint %} {% embed url="" %} *** ## Step 4: Configure trigger conditions Trigger conditions define **when** the rule blocks checkout. By default, rules apply to all orders. {% embed url="" %} ### Two modes | Mode | Behavior | | --------------------------- | ------------------------------------------------------------------- | | **No condition** | Rule **always** applies to all orders | | **When conditions are met** | Rule only applies when **all** conditions are satisfied (AND logic) | ### Available condition types When you select **When conditions are met**, a condition builder appears. Click **"+ Add 'AND' condition"** to add rows. | Condition | Operators | Example | | -------------------- | --------------------------------------------------------------------- | ---------------------------------------------------------- | | **Product** | Contains / Does not contain | Cart contains "Fragile Item" → block checkout with warning | | **Product quantity** | Greater than / Greater than or equal / Less than / Less than or equal | Product quantity > 10 → block bulk orders | | **Cart total** | Greater than / Greater than or equal / Less than / Less than or equal | Cart total < $50 → require minimum order | | **Cart quantity** | Greater than / Greater than or equal / Less than / Less than or equal | Cart quantity > 20 → limit total items | {% hint style="info" %} All conditions use **AND logic** — every condition must be true for the rule to trigger. For example: "Cart total < $50" AND "Cart contains Product A" means both must be satisfied for the error to show. {% endhint %} *** ## Step 5: Configure error message and position This section controls what buyers see when the rule triggers. {% embed url="" %} ### Error message Enter the message buyers will see at checkout. Keep it clear and helpful — explain what they need to do (e.g., "Your order must be at least $50 to proceed. Please add more items."). Maximum **200 characters** recommended. A character counter is shown below the field. ### Error position Choose where the error message appears on the checkout page: | Position | Display | | ---------------------------- | ------------------------------------------------ | | **Top of the checkout page** | Red banner at the top of the page — most visible | | **First name** | Inline error below the First name field | | **Last name** | Inline error below the Last name field | | **Company** | Inline error below the Company field | | **Address line 1** | Inline error below Address line 1 | | **Address line 2** | Inline error below Address line 2 | | **City** | Inline error below the City field | | **Email or phone number** | Inline error below the Email/Phone field | | **Delivery phone** | Inline error below the Delivery phone field | | **ZIP / Postal code** | Inline error below the ZIP code field | | **Country** | Inline error below the Country dropdown | | **Province / State** | Inline error below the Province/State dropdown | {% hint style="warning" %} **"Top of the checkout page"** is recommended for most rules — it's the most visible position and doesn't confuse buyers into thinking a specific field has an error. {% endhint %} *** ## Step 6: Preview and save The right sidebar shows a **live preview** of how your error message will appear based on the selected position. {% embed url="" %} ### Full checkout preview Click **"Preview in checkout"** to open a full-screen modal showing the complete checkout layout with your error message rendered at the correct position. {% embed url="" %} When everything looks good: 1. Set the **Status** to your preferred option 2. Click **Save** in the top bar The rule takes effect at checkout immediately. *** ## Test your rule with Test Mode Before activating a rule for all customers, test it first: 1. Set the rule **Status** to **Test mode** and save 2. Go to your store and add products to the cart 3. Proceed to checkout 4. Enter **** as the checkout email 5. Make sure all trigger conditions (if any) are met 6. Verify the error message appears at the correct position 7. Once verified, change the status to **Active** {% hint style="warning" %} **Test mode only works with the email .** All trigger conditions must also be satisfied for the rule to take effect. {% endhint %} *** ## Manage existing rules ### Toggle status Use the **Pause** / **Start** action on any rule to quickly toggle its status without opening the editor. ### Edit a rule Click the **edit icon** (pencil) in the Actions column, or click the rule name to open the editor. ### Delete rules * **Single rule:** Click the **delete icon** (trash) in the Actions column * **Bulk delete:** Select multiple rules with checkboxes → click **Delete rules** Other bulk actions: **Activate rules**, **Deactivate rules**. {% hint style="warning" %} Deletion is permanent. The rule cannot be recovered. {% endhint %} *** ## Tips * **Start with Test mode** — verify the rule works correctly before activating for all customers * **Use "Top of the checkout page"** for most rules — it's the most visible and avoids field-level confusion * **Keep messages actionable** — tell buyers what to do, not just what went wrong (e.g., "Add at least 2 items" instead of "Not enough items") * **Combine conditions wisely** — all conditions use AND logic, so the rule only triggers when every condition matches * **Keep rule names descriptive** — "Min order $50 for wholesale" is better than "Rule #1" * **Check the limits** — Shopify allows up to 25 active validation rules at once *** ## FAQs ### General **Q: Do I need Shopify Plus for Custom Rules?** A: No. Custom Rules uses Shopify Functions, which are available on all Shopify plans. **Q: How many rules can I have?** A: You can have up to **25 active validation rules** at once (shared with Geo Restriction rules). **Q: Do rules take effect immediately after saving?** A: Yes. Once a rule is set to **Active** and saved, it applies to all new checkouts immediately. ### Trigger conditions **Q: What happens if I set no conditions?** A: The rule applies to every order at checkout. The error message will always show. **Q: Can I combine multiple conditions?** A: Yes. Add multiple conditions with AND logic — all must be true for the rule to trigger. **Q: Does "Product" condition check variants?** A: It checks at the product level. If any variant of the selected product is in the cart, the condition is met. **Q: What's the difference between "Greater than" and "Greater than or equal"?** A: "Greater than 10" means 11 or more. "Greater than or equal to 10" means 10 or more. ### Error message **Q: Can I use different languages in the error message?** A: Yes. Enter the message in any language you prefer — it will display exactly as typed. **Q: What happens if multiple rules trigger at the same time?** A: All matching rules display their error messages. Buyers must resolve all errors before completing checkout. **Q: Does the error block checkout or just show a warning?** A: The error **blocks checkout** — buyers cannot complete their purchase until the condition is no longer met. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://help.aov.ai/aov.ai-checkout-upsell/checkout-validations/custom-rules.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.