> ## 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.

# Pre-fill Firmhouse Checkout fields

> Pre-fill Firmhouse Checkout fields via URL parameters to save customers time, increase conversion rates, and personalize the subscription signup flow.

Save your customers time and increase conversion rates by filling the checkout fields in advance.

Time is valuable for both you and your customers. The less friction there is during checkout, the higher your conversion rate. That's why we offer the option to redirect customers to a checkout that has their data already loaded and ready to go.

So how does this work? It's simple.

## Create the subscription

First, you have to create a subscription using the `createSubscription` mutation. Include the customer's address and contact details, and maybe even Ordered Products. If needed, you can edit these details later with the `updateAddressDetails` mutation.

Make sure that you get the subscription's `token` from the mutation's response.

## Build the checkout URL

Now that the subscription is ready and you have the token, you can then redirect the customer to the checkout page. In the checkout URL, include the subscription's `token` as a `cart_token` attribute.

For example, if the token for the subscription is `abcde12345`, the checkout URL could look like this:

```
https://yourcheckouturl.com?products={product_slug}&cart_token=abcde12345
```

> The above example includes optional product slug, see [Build advanced checkout URLs](/configure/firmhouse-checkout/advanced-checkout-urls) for more information about how this works.

When the customer clicks on this link, they will be directed to the checkout page with all their data already loaded.

So next time you redirect a customer to our checkout, consider using this feature to make their experience even smoother. Happy selling!