Discount Ninja is designed to overcome a number of limitations in how Shopify's standard discount codes and automatic codes work.
These limitations are baked into the standard checkout of Shopify. As a result, Discount Ninja needs to be able to send you to a checkout generated by the app that applies your discount rules.
You can read more about the checkout process here.
Recharge: limited compatibility
The app can be combined with Recharge (older version), which uses a custom checkout. To ensure compatibility, please tag your subscription products with a tag "Subscription" (case doesn't matter).
Here's what to expect when working with Recharge:
A cart that does not contain subscription products is processed by Discount Ninja.
A cart that contains at least one subscription product will be processed by Recharge. Any Discount Ninja promotions applicable to the cart will not be processed.
The app is not yet compatible with the newer version of the Recharge app which uses the standard checkout.
For those reasons, the app cannot be combined with:
Shopify's native automatic discounts since they overrule discounts at the checkout
Shopify's "buy now" buttons and "express checkout" buttons
Apps that redirect to a non-standard Shopify checkout.
Apps that redirect to a checkout without submitting the cart form
Categories of apps with compatibility problems
Apps that redirect to a multi-currency checkout
Apps that redirect to a subscription product checkout
Apps that create upsells on a separate checkout flow
Apps that provide a "one-click" buy option
Apps that execute logic when the checkout button is clicked
Apps that redirect to the checkout using a /checkout link instead of submitting the cart form
List of apps with known compatibility problems
Zipify OCU pre-checkout upsells
Smart Offers by Smartify Apps (not listed on the App Store)