# Add custom fields

Add additional fields to a prebuilt payment page with Checkout.

You can add custom fields on the payment form to collect additional information from your customers. The information is available after the payment is complete and is useful for fulfilling the purchase.

Custom fields have the following limitations:

- Up to three fields allowed.
- Not available in `setup` mode.
- Support for up to 255 characters on text fields.
- Support for up to 255 digits on numeric fields.
- Support for up to 200 options on dropdown fields.

> Don’t use custom fields to collect personal, protected, or sensitive data, or information restricted by law.

## Create a Checkout Session

Create a Checkout Session while specifying an array of [custom fields](https://docs.stripe.com/api/checkout/sessions/create.md#create_checkout_session-custom_fields). Each field must have a unique `key` that your integration uses to reconcile the field. Also provide a label for the field that you display to your customer. Labels for custom fields aren’t translated, but you can use the [locale](https://docs.stripe.com/api/checkout/sessions/create.md#create_checkout_session-locale) parameter to set the language of your Checkout Session to match the same language as your labels.

#### Stripe-hosted page

```curl
curl https://api.stripe.com/v1/checkout/sessions \
  -u "<<YOUR_SECRET_KEY>>:" \
  -d mode=payment \
  --data-urlencode success_url="https://example.com/success" \
  -d "line_items[0][price]"="{{PRICE_ID}}" \
  -d "line_items[0][quantity]"=1 \
  -d "custom_fields[0][key]"=engraving \
  -d "custom_fields[0][label][type]"=custom \
  -d "custom_fields[0][label][custom]"="Personalized engraving" \
  -d "custom_fields[0][type]"=text
```

#### Embedded form

```curl
curl https://api.stripe.com/v1/checkout/sessions \
  -u "<<YOUR_SECRET_KEY>>:" \
  -d mode=payment \
  -d ui_mode=embedded \
  --data-urlencode return_url="https://example.com/return" \
  -d "line_items[0][price]"="{{PRICE_ID}}" \
  -d "line_items[0][quantity]"=1 \
  -d "custom_fields[0][key]"=engraving \
  -d "custom_fields[0][label][type]"=custom \
  -d "custom_fields[0][label][custom]"="Personalized engraving" \
  -d "custom_fields[0][type]"=text
```
![](https://d37ugbyn3rpeym.cloudfront.net/videos/checkout/custom_fields_embedded.mov)
## Retrieve custom fields

When your customer completes the Checkout Session, we send a [checkout.session.completed](https://docs.stripe.com/api/events/types.md#event_types-checkout.session.completed) *webhook* (A webhook is a real-time push notification sent to your application as a JSON payload through HTTPS requests) with the completed fields.

Example `checkout.session.completed` payload:

```json
{
  "id": "evt_1Ep24XHssDVaQm2PpwS19Yt0",
  "object": "event",
  "api_version": "2022-11-15",
  "created": 1664928000,
  "data": {
    "object": {
      "id": "cs_test_MlZAaTXUMHjWZ7DcXjusJnDU4MxPalbtL5eYrmS2GKxqscDtpJq8QM0k",
      "object": "checkout.session","custom_fields": [{
        "key": "engraving",
        "label": {
          "type": "custom",
          "custom": "Personalized engraving"
        },
        "optional": false,
        "type": "text",
        "text": {
          "value": "Jane"
        }
      }],
      "mode": "payment"
    }
  },
  "livemode": false,
  "pending_webhooks": 1,
  "request": {
    "id": null,
    "idempotency_key": null
  },
  "type": "checkout.session.completed"
}
```

You can also look up and edit custom field values from the Dashboard, by clicking into a specific payment in the [Transactions](https://dashboard.stripe.com/payments) tab or including custom field values when exporting your payments from the [Dashboard](https://dashboard.stripe.com/payments).

## Use a custom field

### Mark a field as optional 

By default, customers must complete all fields before completing payment. To mark a field as optional, pass in `optional=true`.

#### Stripe-hosted page

```curl
curl https://api.stripe.com/v1/checkout/sessions \
  -u "<<YOUR_SECRET_KEY>>:" \
  -d mode=payment \
  --data-urlencode success_url="https://example.com/success" \
  -d "line_items[0][price]"="{{PRICE_ID}}" \
  -d "line_items[0][quantity]"=1 \
  -d "custom_fields[0][key]"=engraving \
  -d "custom_fields[0][label][type]"=custom \
  -d "custom_fields[0][label][custom]"="Personalized engraving" \
  -d "custom_fields[0][type]"=text \
  -d "custom_fields[0][optional]"=true
```

#### Embedded form

```curl
curl https://api.stripe.com/v1/checkout/sessions \
  -u "<<YOUR_SECRET_KEY>>:" \
  -d mode=payment \
  -d ui_mode=embedded \
  --data-urlencode return_url="https://example.com/return" \
  -d "line_items[0][price]"="{{PRICE_ID}}" \
  -d "line_items[0][quantity]"=1 \
  -d "custom_fields[0][key]"=engraving \
  -d "custom_fields[0][label][type]"=custom \
  -d "custom_fields[0][label][custom]"="Personalized engraving" \
  -d "custom_fields[0][type]"=text \
  -d "custom_fields[0][optional]"=true
```
![](https://b.stripecdn.com/docs-statics-srv/assets/optional.bf0c1564296ff02264bd5e8c066a6034.png)

### Add a dropdown field 

A dropdown field presents your customers with a list of options to select from. To create a dropdown field, specify `type=dropdown` and a list of options, each with a `label` and a `value`. The `label` displays to the customer while your integration uses the `value` to reconcile which option the customer selected.

#### Stripe-hosted page

```curl
curl https://api.stripe.com/v1/checkout/sessions \
  -u "<<YOUR_SECRET_KEY>>:" \
  -d mode=payment \
  --data-urlencode success_url="https://example.com/success" \
  -d "line_items[0][price]"="{{PRICE_ID}}" \
  -d "line_items[0][quantity]"=1 \
  -d "custom_fields[0][key]"=sample \
  -d "custom_fields[0][label][type]"=custom \
  -d "custom_fields[0][label][custom]"="Free sample" \
  -d "custom_fields[0][optional]"=true \
  -d "custom_fields[0][type]"=dropdown \
  -d "custom_fields[0][dropdown][options][0][label]"="Balm sample" \
  -d "custom_fields[0][dropdown][options][0][value]"=balm \
  -d "custom_fields[0][dropdown][options][1][label]"="BB cream sample" \
  -d "custom_fields[0][dropdown][options][1][value]"=cream
```

#### Embedded form

```curl
curl https://api.stripe.com/v1/checkout/sessions \
  -u "<<YOUR_SECRET_KEY>>:" \
  -d mode=payment \
  -d ui_mode=embedded \
  --data-urlencode return_url="https://example.com/return" \
  -d "line_items[0][price]"="{{PRICE_ID}}" \
  -d "line_items[0][quantity]"=1 \
  -d "custom_fields[0][key]"=sample \
  -d "custom_fields[0][label][type]"=custom \
  -d "custom_fields[0][label][custom]"="Free sample" \
  -d "custom_fields[0][optional]"=true \
  -d "custom_fields[0][type]"=dropdown \
  -d "custom_fields[0][dropdown][options][0][label]"="Balm sample" \
  -d "custom_fields[0][dropdown][options][0][value]"=balm \
  -d "custom_fields[0][dropdown][options][1][label]"="BB cream sample" \
  -d "custom_fields[0][dropdown][options][1][value]"=cream
```
![A checkout page with a dropdown field](https://b.stripecdn.com/docs-statics-srv/assets/dropdown.4501d199ebe009030c2be6935cfdf2dd.png)

### Add a numbers only field 

A numbers-only field provides your customers a text field that only accepts numerical values, up to 255 digits. To create a numbers-only field, specify `type=numeric`.

#### Stripe-hosted page

```curl
curl https://api.stripe.com/v1/checkout/sessions \
  -u "<<YOUR_SECRET_KEY>>:" \
  -d mode=payment \
  --data-urlencode success_url="https://example.com/success" \
  -d "line_items[0][price]"="{{PRICE_ID}}" \
  -d "line_items[0][quantity]"=1 \
  -d "custom_fields[0][key]"=invoice \
  -d "custom_fields[0][label][type]"=custom \
  -d "custom_fields[0][label][custom]"="Invoice number" \
  -d "custom_fields[0][type]"=numeric
```

#### Embedded form

```curl
curl https://api.stripe.com/v1/checkout/sessions \
  -u "<<YOUR_SECRET_KEY>>:" \
  -d mode=payment \
  -d ui_mode=embedded \
  --data-urlencode return_url="https://example.com/return" \
  -d "line_items[0][price]"="{{PRICE_ID}}" \
  -d "line_items[0][quantity]"=1 \
  -d "custom_fields[0][key]"=invoice \
  -d "custom_fields[0][label][type]"=custom \
  -d "custom_fields[0][label][custom]"="Invoice number" \
  -d "custom_fields[0][type]"=numeric
```

### Retrieve custom fields for a subscription 

You can retrieve the custom fields associated with a subscription by querying for the Checkout Session that created it using the [subscription](https://docs.stripe.com/api/checkout/sessions/list.md#list_checkout_sessions-subscription) parameter.

```curl
curl -G https://api.stripe.com/v1/checkout/sessions \
  -u "<<YOUR_SECRET_KEY>>:" \
  -d subscription="{{SUBSCRIPTION_ID}}"
```

### Add character length validations 

You can optionally specify a minimum and maximum character length [requirement](https://docs.stripe.com/api/checkout/sessions/create.md#create_checkout_session-custom_fields-numeric-maximum_length) for `text` and `numeric` field types.

#### Stripe-hosted page

```curl
curl https://api.stripe.com/v1/checkout/sessions \
  -u "<<YOUR_SECRET_KEY>>:" \
  -d mode=payment \
  --data-urlencode success_url="https://example.com/success" \
  -d "line_items[0][price]"="{{PRICE_ID}}" \
  -d "line_items[0][quantity]"=1 \
  -d "custom_fields[0][key]"=engraving \
  -d "custom_fields[0][label][type]"=custom \
  -d "custom_fields[0][label][custom]"="Personalized engraving" \
  -d "custom_fields[0][type]"=text \
  -d "custom_fields[0][text][minimum_length]"=10 \
  -d "custom_fields[0][text][maximum_length]"=20 \
  -d "custom_fields[0][optional]"=true
```

#### Embedded form

```curl
curl https://api.stripe.com/v1/checkout/sessions \
  -u "<<YOUR_SECRET_KEY>>:" \
  -d mode=payment \
  -d ui_mode=embedded \
  --data-urlencode return_url="https://example.com/return" \
  -d "line_items[0][price]"="{{PRICE_ID}}" \
  -d "line_items[0][quantity]"=1 \
  -d "custom_fields[0][key]"=engraving \
  -d "custom_fields[0][label][type]"=custom \
  -d "custom_fields[0][label][custom]"="Personalized engraving" \
  -d "custom_fields[0][type]"=text \
  -d "custom_fields[0][text][minimum_length]"=10 \
  -d "custom_fields[0][text][maximum_length]"=20 \
  -d "custom_fields[0][optional]"=true
```
![A field with character limits](https://b.stripecdn.com/docs-statics-srv/assets/between-validation.20431cd8e0c03a028843945d1f1ea314.png)

### Add default values 

You can optionally provide a default value for the [text](https://docs.stripe.com/api/checkout/sessions/create.md#create_checkout_session-custom_fields-text-default_value), [numeric](https://docs.stripe.com/api/checkout/sessions/create.md#create_checkout_session-custom_fields-numeric-default_value), and [dropdown](https://docs.stripe.com/api/checkout/sessions/create.md#create_checkout_session-custom_fields-dropdown-default_value) field types. Default values are prefilled on the payment page.

#### Stripe-hosted page

```curl
curl https://api.stripe.com/v1/checkout/sessions \
  -u "<<YOUR_SECRET_KEY>>:" \
  -d mode=payment \
  --data-urlencode success_url="https://example.com/success" \
  -d "line_items[0][price]"="{{PRICE_ID}}" \
  -d "line_items[0][quantity]"=1 \
  -d "custom_fields[0][key]"=engraving \
  -d "custom_fields[0][label][type]"=custom \
  -d "custom_fields[0][label][custom]"="Personalized engraving" \
  -d "custom_fields[0][type]"=text \
  -d "custom_fields[0][text][default_value]"=Stella \
  -d "custom_fields[1][key]"=size \
  -d "custom_fields[1][label][type]"=custom \
  -d "custom_fields[1][label][custom]"=Size \
  -d "custom_fields[1][type]"=dropdown \
  -d "custom_fields[1][dropdown][default_value]"=small \
  -d "custom_fields[1][dropdown][options][0][value]"=small \
  -d "custom_fields[1][dropdown][options][0][label]"=Small \
  -d "custom_fields[1][dropdown][options][1][value]"=large \
  -d "custom_fields[1][dropdown][options][1][label]"=Large
```

#### Embedded form

```curl
curl https://api.stripe.com/v1/checkout/sessions \
  -u "<<YOUR_SECRET_KEY>>:" \
  -d mode=payment \
  -d ui_mode=embedded \
  --data-urlencode return_url="https://example.com/return" \
  -d "line_items[0][price]"="{{PRICE_ID}}" \
  -d "line_items[0][quantity]"=1 \
  -d "custom_fields[0][key]"=engraving \
  -d "custom_fields[0][label][type]"=custom \
  -d "custom_fields[0][label][custom]"="Personalized engraving" \
  -d "custom_fields[0][type]"=text \
  -d "custom_fields[0][text][default_value]"=Stella \
  -d "custom_fields[1][key]"=size \
  -d "custom_fields[1][label][type]"=custom \
  -d "custom_fields[1][label][custom]"=Size \
  -d "custom_fields[1][type]"=dropdown \
  -d "custom_fields[1][dropdown][default_value]"=small \
  -d "custom_fields[1][dropdown][options][0][value]"=small \
  -d "custom_fields[1][dropdown][options][0][label]"=Small \
  -d "custom_fields[1][dropdown][options][1][value]"=large \
  -d "custom_fields[1][dropdown][options][1][label]"=Large
```