> ## Documentation Index
> Fetch the complete documentation index at: https://docs.firmhouse.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Compatible Shopify plugins

> List of Shopify plugins confirmed compatible with Shopify Native Checkout and Firmhouse subscriptions, plus how to request a compatibility review.

This article covers a list of Shopify plugins with which we have confirmed compatibility. If you're looking into using a plugin that is not in this list, please reach out for our team to advise on compatibility and potential extra steps.

## Cart Plugins

### Upcart—Cart Drawer Cart Upsell

[Upcart—Cart Drawer Cart Upsell](https://apps.shopify.com/upcart-cart-builder) is compatible with Firmhouse.

To make sure your setup works correctly:

1. Add `.upcart-checkout-button,button[name='checkout']` to the **Original Checkout Button Selector** setting on the Checkout Button Injector app embed.

<img src="https://mintcdn.com/firmhousebv/i0tAuZcoMZU4WKIb/images/checkout_button_injector_settings.png?fit=max&auto=format&n=i0tAuZcoMZU4WKIb&q=85&s=02f3f06ef2afae83f2170b6d07e5a8b1" alt="checkout_button_injector_settings" width="800" height="400" data-path="images/checkout_button_injector_settings.png" />

2. Disable the [Render Cart in Shadow DOM](https://intercom.help/as-upcart/en/articles/126) setting for the Upcart Cart, under **Upcart → Settings → Advanced Settings**.

### Monster Cart Upsell+Free Gift

[Monster Cart Upsell+Free Gift](https://apps.shopify.com/monster-upsells) is compatible with Firmhouse.

To make sure your setup works correctly, add `#mu-checkout-button` to the **Original Checkout Button Selector** setting on the Checkout Button Injector app embed.

<img src="https://mintcdn.com/firmhousebv/dE5H2KMQTvd0k7qC/images/monster_checkout_button_selector.png?fit=max&auto=format&n=dE5H2KMQTvd0k7qC&q=85&s=d947be3c03643372d08a572f20554034" alt="monster_checkout_button_selector" width="800" height="400" data-path="images/monster_checkout_button_selector.png" />

## Product Bundles for Subscriptions

### Bundles.app — Inventory Sync

[Bundles.app — Inventory Sync](https://apps.shopify.com/bundles) allows you to offer product bundles on subscription and is fully compatible with Firmhouse.

## Add a Free Gift to the First Subscription Order

### EG Auto Add to Cart Free Gift

[EG Auto Add to Cart Free Gift](https://apps.shopify.com/gifter-cart-auto-inclu) allows you to add a free gift to the checkout order. Due to its capability to select products and selling plans configurations, this will enable you to add a free gift on subscription checkouts (and not on one-time purchases).

## Add an Additional Fee to the Checkout Order

### UpCharge Fees Addons Surcharge

[UpCharge Fees Addons Surcharge](https://apps.shopify.com/product-fees) allows you to add a one-time extra fee on the checkout order and is fully compatible with Firmhouse. Recurring orders will not get a surcharge.