# Adding custom fields
If you’d like to collect additional customer information during a [low-code checkout](https://docs.digitalriver.com/digital-river-api/integration-options/low-code-checkouts), you can add custom fields to the experience.
Digital River adds what these fields contain to the [checkout-session](https://app.gitbook.com/s/x8fSFzVR3sg0TsNWwwVz/drop-in-checkout-sessions#drop-in-checkout-sessions) so that you can use it in downstream processes.
## Setup custom fields
On [Digital River Dashboard’s Prebuilt Checkout page](https://docs.digitalriver.com/digital-river-api/administration/dashboard/settings/prebuilt-checkout), you can configure a maximum of two custom fields, each of which can accept a number, text (i.e., string), or a set of pre-defined drop-down options.
For each field, you need to:
* Indicate whether it’s required or optional.
{% hint style="warning" %}
If you mark it as required, then express checkout is disabled in [Prebuilt Checkout](https://docs.digitalriver.com/digital-river-api/integration-options/low-code-checkouts/drop-in-checkout).
{% endhint %}
* Define a unique key and make sure it contains no whitespaces.
* Define a label that will be displayed to customers in the experience.
If you’re using the drop-down field, you must enumerate acceptable values and provide a display label for each.
## The checkout experience
Depending on whether you add [physical or digital-only products](https://docs.digitalriver.com/digital-river-api/product-management/skus#how-products-are-classified-as-physical-or-digital) to the [checkout-session’s](https://app.gitbook.com/s/x8fSFzVR3sg0TsNWwwVz/drop-in-checkout-sessions/checkout-sessions-basics) [`items[]`](https://app.gitbook.com/s/x8fSFzVR3sg0TsNWwwVz/drop-in-checkout-sessions/checkout-sessions-basics#product-data)Digital River renders your custom fields in the shipping or billing information forms.
{% tabs %}
{% tab title="Prebuilt Checkout" %}
**Physical products in `items[]`**
{% endtab %}
{% endtabs %}
If you mark a field as required and customers don't provide a value, they are prompted for input.
{% tabs %}
{% tab title="Prebuilt Checkout" %}
{% endtab %}
{% tab title="Address Component" %}
{% endtab %}
{% endtabs %}
Number-only fields provide help text if customers enter a non-digit character.
{% tabs %}
{% tab title="Prebuilt Checkout" %}
{% endtab %}
{% tab title="Address Component" %}
{% endtab %}
{% endtabs %}
Number and text fields accept values with a maximum length of 500 characters.
Labels aren't translated into the [`language` ](https://app.gitbook.com/s/x8fSFzVR3sg0TsNWwwVz/drop-in-checkout-sessions/checkout-sessions-basics#language)of the [checkout-session](https://app.gitbook.com/s/x8fSFzVR3sg0TsNWwwVz/drop-in-checkout-sessions), but instead default to English.
## Implement custom fields in Components
The [`done()`](https://docs.digitalriver.com/digital-river-api/integration-options/implementing-a-components-checkout#submitting-components) function, which submits the data collected by the [address component](https://docs.digitalriver.com/digital-river-api/developer-resources/digitalrivercheckout.js-reference/digitalrivercheckout-object/components/address-component) in an update [checkout-session](https://app.gitbook.com/s/x8fSFzVR3sg0TsNWwwVz/drop-in-checkout-sessions) request, returns `false` if the user (1) fails to enter a value in a custom field that you marked as required or (2) enters a value that exceeds 500 characters in a custom number or text field.
If your application is set up correctly, this should block customers from proceeding to the checkout's next stage.
For details, refer to [Controlling the checkout flow](https://docs.digitalriver.com/digital-river-api/integration-options/implementing-a-components-checkout#controlling-the-checkout-flow).
You might want to disable the [wallet component](https://docs.digitalriver.com/digital-river-api/developer-resources/digitalrivercheckout.js-reference/digitalrivercheckout-object/components/wallet-component), if you [mark a custom field as required in the Digital River Dashboard](#setup-custom-fields), When users click a button in this component, they are redirected to a payment provider. However, the form in the provider's interface lacks a field to collect your custom data, so it won't get added to the [checkout-session](https://app.gitbook.com/s/x8fSFzVR3sg0TsNWwwVz/drop-in-checkout-sessions/checkout-sessions-basics).
## Retrieve the collected data
After customers successfully submit the form, Digital River adds the key and value of each field they completed to the [checkout-session’s](https://app.gitbook.com/s/x8fSFzVR3sg0TsNWwwVz/drop-in-checkout-sessions#drop-in-checkout-sessions) `metadata`.
You can access this data by:
* [Configuring a webhook](https://docs.digitalriver.com/digital-river-api/order-management/events-and-webhooks-1/webhooks/creating-a-webhook) to listen for certain [types](https://docs.digitalriver.com/digital-river-api/order-management/events-and-webhooks-1/events-1#event-types) of [events](https://app.gitbook.com/s/x8fSFzVR3sg0TsNWwwVz/events), such as [`checkout_session.order.created`](https://docs.digitalriver.com/digital-river-api/order-management/events-and-webhooks-1/events-1/event-types#checkout_session.order.created), [`order.accepted`](https://docs.digitalriver.com/digital-river-api/order-management/events-and-webhooks-1/events-1/event-types#order.accepted), [`fulfillment.created`](https://docs.digitalriver.com/digital-river-api/order-management/events-and-webhooks-1/events-1/event-types#fulfillment.created), `order.fulfilled`, and [`order.refunded`](https://docs.digitalriver.com/digital-river-api/order-management/events-and-webhooks-1/events-1/event-types#order.refunded).
{% tabs %}
{% tab title="order.accepted" %}
```json
{
"id": "66524f24-74d5-4356-b30f-ff1da95db3eb",
"type": "order.accepted",
"data": {
"object": {
"id": "295121620336",
...
"metadata": {
"freeSample": "chewToy",
"giftCardMessage": "A special treat for Zoey's birthday"
},
...
}
},
...
}
```
{% endtab %}
{% tab title="fulfillment.created" %}
{% code title="Event" %}
```json
{
"id": "9baea62d-cec5-49e1-b8ac-8546b2007e8d",
"type": "fulfillment.created",
"data": {
"object": {
"id": "ful_854dee4b-cf4b-43b9-aecb-89d46a9f96cf",
...
"orderDetails": {
"id": "295121620336",
...
"metadata": {
"freeSample": "chewToy",
"giftCardMessage": "A special treat for Zoey's birthday"
},
...
}
}
},
...
}
```
{% endcode %}
{% endtab %}
{% endtabs %}
* Assigning a callback to [`onCheckoutComplete`](https://docs.digitalriver.com/digital-river-api/developer-resources/digitalrivercheckout.js-reference/digitalrivercheckout-object/configuring-prebuilt-checkout#oncheckoutcomplete) in [Prebuilt Checkout's configuration object](https://docs.digitalriver.com/digital-river-api/developer-resources/digitalrivercheckout.js-reference/digitalrivercheckout-object/configuring-prebuilt-checkout) and then implementing a handler.
* Assigning a callback to [`onSuccess`](https://docs.digitalriver.com/digital-river-api/developer-resources/digitalrivercheckout.js-reference/digitalrivercheckout-object/components/configuring-components#success-event) in the [Component's configuration object](https://docs.digitalriver.com/digital-river-api/developer-resources/digitalrivercheckout.js-reference/digitalrivercheckout-object/components/configuring-components) and then implementing a handler.
* Making a call to [retrieve the order](https://app.gitbook.com/s/x8fSFzVR3sg0TsNWwwVz/orders#orders).
Once you have this `metadata`, you can use it to populate email notifications, fulfill an order’s goods, or perform other operations of your choice.
