Using Downpay with product options apps
Using a product options app with Downpay requires some specific setup to make sure deposits apply to the full order, not just the base product. This guide covers what to look for and how to configure it correctly.
On this page:
Setting up Downpay with a product options app
Compatible apps and setup guides
Overview
Many Shopify merchants use a product options app to let customers configure a product before buying. For example, a furniture brand might offer fabric, leg finish, and custom sizing as paid add-ons. When a deposit is involved, that deposit should apply to the full cart total including those options.
Downpay is compatible with many product options apps, but not all. Whether an app works with Downpay depends on how it adds options and extra fees to the cart under the hood.
How compatibility works
For Downpay to apply a deposit to a product option or add-on, two things must be true:
- The option must exist as a real product or variant in Shopify. Downpay works by assigning products and variants to a purchase option. If an add-on fee is not tied to a real Shopify product or variant, Downpay has no way to include it in the deposit calculation.
- The selling plan must carry through to the cart. When a customer selects a deposit, Downpay attaches a
selling_planto the cart request. If the product options app has its own add to cart flow that does not pass theselling_planthrough, the deposit will not apply and troubleshooting might be required. Learn more about how to fix with this issue.
Why some options apps are not compatible
There are three main reasons a product options app may not work with Downpay:
Cart Transform API
Some apps use Shopify's newer Cart Transform API to apply add-ons and fees. Shopify's Cart Transform system does not currently support selling plans, which means Downpay cannot attach a deposit when this method is in use. Some apps offer a setting to disable Cart Transform, which restores compatibility. View Shopify compatibility documentation.
Draft orders
Some apps use Shopify's draft orders API to add options to the cart and charge extra fees at checkout. As covered in our deposits and draft orders guide, Shopify draft orders do not support selling plans. If an app relies on draft orders, it will not be compatible with Downpay.
Custom add to cart flows
Some apps override Shopify's default add to cart behaviour with their own code. When this happens, the selling_plan that Downpay injects into the product form does not get included in the cart request. The result is that the product is added to the cart without a deposit attached. Learn more about how to fix with this issue.
Setting up Downpay with a product options app
If options do not affect price
If the options your customers select do not add any extra fees to the order, no special setup is needed and most apps work just fine. Downpay will calculate the deposit correctly based on the product price alone.
If options affect price
If your options add extra fees to the cart and you want the deposit to apply to the full total including those fees, follow these steps.
- Set up your options inside your chosen product options app
- Make sure each paid option is tied to a real product or variant in Shopify
- In Downpay, open the relevant purchase option and add the main product along with all option products or variants to the same purchase option
- Set your deposit as a percentage rather than a fixed amount. Downpay can only calculate partial payment across a main product and its add-ons using percentage-based deposits.
- Make sure your store directs customers to the full cart page before checkout. Downpay needs to see the complete cart total before the deposit amount can be calculated correctly.
- Test by adding the main product and one or more paid options, then navigate to the cart page and confirm the deposit calculation reflects the full subtotal.
Compatible apps and setup guides
These are the product options apps we have tested and confirmed work with Downpay. For apps not listed here, see our full compatibility list.
APO Product Options, Variants
APO Product Options, Variants is compatible with Downpay.
Dynamic Product Options
Dynamic Product Options is compatible with Downpay with one required setting change.
Full setup steps coming soon.
Infinite Product Options
Infinite Product Options is compatible with Downpay with one required setting change.
Full setup steps coming soon.
Zepto Product Customization
Zepto Product Customization is compatible with Downpay when options are configured correctly.
Steps:
- In Zepto, configure your options using the Link to Variant feature instead of Price Change
- In Downpay, add the main product and all linked variant options to the same purchase option
Full setup steps coming soon.
Other apps
Don't see your app listed? Check our full compatibility list or contact our support team and we'll be happy to test it with you.
Updated on: 15/04/2026
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