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

# Add-ons

> Offer Shopify checkout upsells in Appfox. Customers add paired products to a subscription, billed on the same schedule as the main selling plan.

Add-ons let you offer complementary products during subscription checkout. Customers can add these products to their recurring orders for additional revenue per subscription.

## What are add-ons?

Add-ons are products that customers can add to their subscription at checkout. They appear as optional upsells when a customer is setting up a subscription.

For example, if a customer subscribes to coffee beans, you might offer filters or a coffee mug as add-ons.

Add-ons are billed on the same schedule as the main subscription. If the customer subscribes monthly, the add-on is also charged monthly.

<Note>
  Add-ons are included for every store. Appfox Subscriptions is [free for now](/subscription/docs/subscription/docs/settings/billing), with every feature unlocked.
</Note>

## Configure add-ons

<Steps>
  <Step title="Go to Add-ons settings">
    Click **Growth tools**, then **Add-ons**.
  </Step>

  <Step title="Select products">
    Choose which products to offer as add-ons. These products appear as upsell options during subscription checkout.
  </Step>

  <Step title="Set pairing rules">
    Configure which add-ons appear for which subscription plans. You can show specific add-ons only when customers subscribe to certain products.

    For example, show coffee filters only when customers subscribe to coffee beans.
  </Step>

  <Step title="Save your configuration">
    Click **Save** to activate the add-ons. They will appear in the subscription checkout flow immediately.
  </Step>
</Steps>

## How add-ons work

When a customer creates a subscription, the checkout flow shows available add-ons. The customer can select zero, one, or multiple add-ons to include in their recurring orders.

Add-ons are billed at the same frequency as the main subscription. If the subscription is paused or cancelled, the add-ons are also paused or cancelled.

Customers can add or remove add-ons from their subscriptions at any time through the customer portal.

<Note>
  Add-ons apply to the entire subscription. If a customer has multiple products in their subscription, the add-on is charged once per billing cycle, not once per product.
</Note>

<Tip>
  Choose add-ons that complement your subscription products. The best add-ons are items customers use alongside the main product on the same schedule.
</Tip>

## Related features

* [Growth tools](/subscription/docs/subscription/docs/offers) — Access bundles and add-ons
* [Bundles](/subscription/docs/subscription/docs/bundles) — Sell fixed product sets for one price
* [Build-a-box](/subscription/docs/subscription/docs/build-a-box) — Let customers create custom subscription boxes


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