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Restrict Multi Discount Codes

Limit discount codes at Shopify Plus checkout — how it works

The restrict-discount-codes checkout UI extension limits how many discount codes a customer can apply during checkout. It requires Shopify Plus — checkout UI extensions are not available on standard Shopify plans.

Merchant setting

Section titled “Merchant setting”

In the checkout editor, configure:

Setting Key Type Default
Maximum discount codes allowed max_discount_codes Integer 1

If you leave the setting empty, the extension defaults to 1 code.

Customer experience

Section titled “Customer experience”

Within the limit

Section titled “Within the limit”

When the number of applied discount codes is at or below your maximum, customers see an informational banner reminding them of the limit (for example: “Please be reminded that you can only use 1 discount code(s) at a time.”).

Over the limit

Section titled “Over the limit”

When the customer applies more codes than allowed:

  1. A critical banner appears with the error message.
  2. Checkout progress is blocked — the customer cannot complete the order until they remove extra codes.
  3. An error appears under the discount code field and a page-level error explains what to do.

This uses Shopify’s buyer journey intercept API with block_progress enabled on the extension.

Where the block appears

Section titled “Where the block appears”

The extension targets purchase.checkout.reductions.render-before — the area before discount and gift card reductions in checkout. You choose the exact placement in the checkout editor.

Localization

Section titled “Localization”

The extension ships with translations for many buyer locales (English, Chinese Traditional/Simplified, French, German, and others). Messages adapt to the customer’s checkout language with fallback to English.

Section titled “Related guides”