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

# Listing - Add-on Settings

> Configure how this listing behaves when it is sold as an add-on to other listings

export const userRoleDefinition = "What a user can see and do. Each user has one built-in system role — Owner, Admin, Manager, or Member — and can also be assigned any number of custom roles you create with specific permissions. Effective access is the combination of all their roles.";

<Frame caption="Catalog > Listings > [Listing] > Add-on Settings">
  <img src="https://mintcdn.com/twicecommerce/Ab7tx7ih94KQsi0k/images/catalog-listing-addon.webp?fit=max&auto=format&n=Ab7tx7ih94KQsi0k&q=85&s=cf734e622f543ffc84f68a7f3ce2e0f8" alt="Listing add-on settings tab showing visibility and add-on pricing options" width="1920" height="1080" data-path="images/catalog-listing-addon.webp" />
</Frame>

<Info>
  This view can look different dependent on your user role. <br />See [Visibility & Permissions](#visibility-and-permissions) for details.
</Info>

## Primary Purpose

The Add-on Settings tab configures how **this listing** behaves when other listings offer it as an add-on — for example, an insurance listing sold alongside bike rentals.

<Note>
  Attaching add-ons **to** a listing happens on the [Recommendations](/docs/catalog/listings/recommendations) tab, not here. This tab only controls how this listing acts when it is the add-on.
</Note>

<AccordionGroup>
  <Accordion title="Visibility — Only available as add-on">
    The **Only available as add-on** switch (`addonOnly`) hides this listing from storefront browsing. When enabled, customers can only get it as an add-on on other listings.
  </Accordion>

  <Accordion title="Pricing when sold as add-on">
    The **When sold as add-on** setting (`addonPricingMode`) controls how the add-on price is computed:

    * **Use this listing's own price tables** (`standalone`) — the add-on is priced from its own [Price Tables](/docs/catalog/listings/pricing), like any other listing.
    * **Percentage of parent listing price** (`percentage`) — the add-on price is a percentage (`addonPricePercentage`, a whole number from 1 to 200) applied to the parent listing's subtotal. Percentage-priced add-ons are always sold as a purchase (Buy), not a booking.
  </Accordion>
</AccordionGroup>

## Related Concepts

<AccordionGroup>
  <Accordion title="Attaching add-ons">
    To offer other listings as add-ons on this listing — including the per-link settings for quantity, pre-selection, and required add-ons — use the [Recommendations](/docs/catalog/listings/recommendations) tab.
  </Accordion>

  <Accordion title="Add-ons on Existing Orders">
    From an order's Line Items tab, operators can attach add-ons after checkout — for example, adding a helmet to a bike rental that was already placed. See [Order Line Items](/docs/orders/order-tabs/line-items).

    When you edit a parent line item's dates, any add-on children that share the same purchase type (booking add-on on a booking parent, or sale add-on on a sale parent) automatically inherit the updated start and end dates. Add-ons with a different purchase type keep their original dates.
  </Accordion>
</AccordionGroup>

## Visibility and Permissions

Access to this view is controlled by your <Tooltip tip={userRoleDefinition}>user role</Tooltip>.

<Tabs>
  <Tab title="Visibility" icon="eye">
    | Feature      | Admin | Manager | Member |
    | ------------ | :---: | :-----: | :----: |
    | View Add-ons |   ✓   |    ✓    |    ✓   |
    | Edit Add-ons |   ✓   |    ✓    |    ✗   |
  </Tab>
</Tabs>