NMI Payment Gateway Setup

NMI lets you accept debit and credit card payments for digital products through your own NMI payment gateway account. Connect NMI when you want card checkout handled through your merchant account while SellApp manages the order, delivery, and product-level payment settings.

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Add NMI

Open Payment settings, then open NMI.

Enter:

1. Merchant secure key.
2. Merchant tokenization key.
3. Webhook signing key.
4. At least one supported currency.

Then save the method.

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Enable NMI on products

When adding NMI, you can enable it for all existing products. You can also manage payment methods per variant from the product editor or with the Products dashboard bulk payment-method update.

Use product-level controls when only certain listings should accept NMI card payments. For example, you might keep NMI enabled on high-volume digital downloads while leaving another payment method on subscription or manual-review products.

After NMI is removed, SellApp removes unavailable payment methods from variants so customers are not offered a broken checkout option.

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Fees or discounts

Once NMI is active, you can add a payment-method fee or discount.

Use a positive value to discount NMI payments. Use a negative value to charge an extra fee.

For example:

1. 10 in the percentage field gives a 10% discount.
2. -10 in the percentage field adds a 10% fee.
3. 5 in the fixed field gives a fixed discount.
4. -5 in the fixed field adds a fixed fee.

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Configuration issues

If NMI authentication fails during checkout, SellApp can flag the configuration issue so you know the payment method needs attention.

Check the merchant secure key, tokenization key, signing key, and enabled currencies before sending customers back through checkout.