Steps
1. Install Nex Validator
Search Nex Validator in the Shopify App Store, or use the button below. Approve the permissions and the app appears in your admin under Apps. There is a free trial, and it works on every Shopify plan.
2. Open the rule you want to change, or create one.
3. Enable Use custom message and write your text in Custom error message.
4. Save with Status set to Enabled.
What to write
| Instead of | Write |
|---|---|
| ”Minimum order not met" | "Orders start at £50" |
| "Invalid quantity" | "This item is sold in packs of 6" |
| "Cart limit exceeded" | "Limit 2 per order so everyone gets a chance" |
| "Error” | Anything at all |
Verify it worked
Build a cart that breaks the rule and open checkout. Your text should appear in place of the default.
If you also show messages on the cart page, check both surfaces — they render in different places and a message that reads well at checkout can be truncated in a cart drawer.
A note on tone
A block is a refusal, and customers read refusals as the store’s fault. Explaining why costs a few words and measurably softens it — “so everyone gets a chance”, “our workshop produces in batches of 12”. Merchants who add a reason report fewer support messages about it.