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Buy Order Form (F2C)

Introduction

This document describes the steps to take in order to embed the BTC Direct buy order form widget in another website. It is aimed at developers that will implement this functionality.

Implementing the widget

In order to enable the widget in your website, the following script needs to be embedded. This script loads the widget from the BTC Direct CDN (Content Delivery Network) and initializes it automatically.

html
<script lang="js">
    (function (btc, d, i, r, e, c, t) {
        btc[r] = btc[r] || function () {
            (btc[r].q = btc[r].q || []).push(arguments)
        };
        c = d.createElement(i);
        c.id = r; c.src = e; c.async = true;
        c.type = 'module'; c.dataset.btcdirect = '';
        t = d.getElementsByTagName(i)[0];
        t.parentNode.insertBefore(c, t);
    })(window, document, 'script', 'btcdirect',
        'https://cdn.btcdirect.eu/fiat-to-coin/fiat-to-coin.js'
    );

    btcdirect('init', { token: 'API_KEY' });
</script>

If a valid key is provided, and the styling is added, it will result in the following:

Important: Provide wallet address(es)

When implementing the above example, there will be a notification shown instead of the wallet address selector. This is because the widget expects the user’s wallet addresses to be provided in order to select them.

The above preview has (demo) addresses provided and therefore shows the wallet address selector correctly.

Optional init call parameters

The init call, as described in Getting Started, can contain several key-value pairs to fine-tune the widget. The different options are described below.

KeyTypeDescriptionDefault value
returnUrlstringThe url that is used in some places in the widget once the user is redirected to a specific external page of BTC Direct.The url of the page that the widget is loaded in.
useSameWindowForPaymentbooleanSetting this to false opens the payment page in a new window instead of navigating the current window to the payment page.true
walletConfirmationRequiredbooleanIf the order needs to be confirmed via a wallet. If set to true, a message will be emitted from the widget when the user confirms the order.
This needs to be caught and additional information has to be provided to the widget after confirmation on your wallet. See Events emitted by the widget for more information.
false

All widgets support selector, debug, locale and theme.

Additional calls to the widget

The widget accepts several calls to it with which additional information can be provided. These can be added to the script tag that loads the widget.

Set parameters

This call enables you to prefill all that is needed to make a fiat to coin order. All parameters are optional so you only have to add the information you want to have prefilled.

js
btcdirect('set-parameters', {
    baseCurrency: 'BTC',
    quoteCurrency: 'EUR',
    baseCurrencyAmount: 0.001,
    quoteCurrencyAmount: 123,
    paymentMethod: 'creditCard',
    walletAddress: '3FZbgi29cpjq2GjdwV8eyHuJJnkLtktZc5',
    walletAddressTag: '1513155290',
    signature: '67890fghij',
    returnUrl: 'https://btcdirect.eu',
    callbackUrl: 'https://btcdirect.eu',
    partnerOrderIdentifier: '12345abcde',
    fee: 0.5,
    expiryDateTime: 1701423182,
    fixedAmount: true,
    fixedCurrency: true,
    fixedPaymentMethod: true,
    showWalletAddress: true
});

The below table provides more information about each parameter that can be set.

KeyTypeDescription
baseCurrencystringThe cryptocurrency to preselect
quoteCurrencystringThe fiat currency to preselect
baseCurrencyAmountnumberThe crypto amount to prefill
quoteCurrencyAmountnumberThe fiat amount to prefill
paymentMethodstringThe payment method to preselect
walletAddressstringThe wallet address of the user
walletAddressTagstringThe destination tag of the wallet (if applicable)
signaturestringSee sub-chapter "Offer API call parameters" below for more information
returnUrlstringThe url to return to when clicking the "Back to partner" buttons in the flow
callbackUrlstringThe url where updates on the order will be sent to
partnerOrderIdentifierstringYour order ID (if applicable)
feenumberA specific fee for this order (as a percentage)
expiryDateTimestringSee sub-chapter "Offer API call parameters" below for more information
fixedAmountbooleanLock the amounts so they cannot be changed
fixedCurrencybooleanLock the currencies so they cannot be changed
fixedPaymentMethodbooleanLock the payment method so it cannot be changed
showWalletAddressbooleanShow or hide the wallet address of the user

TIP

Note that when providing one of the following parameters, the signature becomes a required field:

  • walletAddress
  • fee
  • returnUrl
  • callbackUrl

INFO

Note that if both baseCurrencyAmount and quoteCurrencyAmount are set, only the quoteCurrencyAmount will be used to prevent mismatch between these when quoting.

Offer API call parameters

The following parameters are mainly used for the Unified checkout flow, but can also be provided to the widget to trigger certain settings or functionalities.

Signature

When using the API to create an offer, the response contains a signature. This signature can be sent to the widget to make sure the same offer will be used for this order.

ExpiryDateTime

When using the API to create an offer, the response contains an expiry date. This Unix timestamp value is used to determine if the offer is not expired.

Locale

This call sets the locale for the application. This determines the way monetary values are displayed. For example 0 Euro’s in the EN-GB locale is displayed as “€0.00” whereas the NL-NL locale results in “€ 0,00”.

js
btcdirect('locale', { locale: 'en-GB' });

Currencies

This call sets the selected currencies for the widget. This is for both the cryptocurrency and the fiat currency. The provided values result in these currencies being selected in the order form as initial values.

js
btcdirect('currencies', { crypto: 'BTC', fiat: 'EUR' });

Order information

It is possible to set up the basic information of an order, making it easier for your users to purchase crypto as most of the form will be pre-filled. In order to do this you can provide both currencies of the order (crypto and fiat), the order amount and if it is a fiat amount or crypto amount.

js
// JavaScript from previous code example
btcdirect('init', { token: 'API_KEY' });

btcdirect('order', {
    crypto: 'LTC',
    fiat: 'EUR',
    amount: 1,
    type: 'crypto'
});

Payment method

This call sets the selected payment method for the order form. The payment methods are only visible once the user has logged in.

js
btcdirect('payment-method', { method: 'iDeal' });

The following payment methods are available.

Payment methodValue to add
Bancontactbancontact
Bank transferbankTransfer
Credit cardcreditCard
Giropaygiropay
iDealiDeal
Sofort Bankingsofort
Apple Payapplepay

Note: In order for Apple Pay to be visible in the list of payment methods, the widget needs to be initialised in Safari on an Apple device. To learn more about compatible devices, visit Apple's documentation.

Callback url

This call sets a callback url to which the result of the order is communicated. For example when setting the url to https://btcdirect.eu it will be called after an order has been completed. The status and ID of the order are added as query parameters, such as ?orderId=123456&status=success. This enables your website to catch the status of the order and display information accordingly.

js
btcdirect('callback', { callbackUrl: 'https://btcdirect.eu' });

The following values can be returned by the process, according to the status of the order:

StatusDescription
successThe order has been processed successfully.
expiredThe order’s payment window has expired. Therefore the order is stopped.
cancelledThe order has been canceled by the user.
deniedThe order has been denied by the payment provider. This is usually when a user tries to pay for an order with insufficient funds.
failedThe order has failed for unknown reasons.

Wallet address confirmation

When the init parameter walletConfirmationRequired parameter is set to true, and the btcdirect-embeddable-fiat-to-coin-order-confirmed is received, the widget needs a confirmation message from your application in order to continue the order. The idea is to have the user confirm the wallet address on your (hardware) wallet. Once the confirmation is done the following message can be sent to the widget confirming the wallet. In this example the address needs to be replaced by the user’s wallet address.

js
btcdirect('wallet-address-confirmation', {
    address: 'address'
});

Canceling wallet address confirmation

It’s possible to send a cancellation to the widget in order to stop the process. This results in the widget returning to the order form.

js
btcdirect('wallet-address-confirmation-canceled');

Events emitted by the widget

The widget also emits events. Listening to these events enables you to respond to specific state changes.

Order confirmation

When a user confirms his order in the order form, the user is redirected to the payment page of the selected payment provided (for example Adyen when selecting credit card). Before the redirect is executed an event is emitted containing the following information.

Event name: btcdirect-embeddable-fiat-to-coin-order-confirmed

js
// event.detail:
{
    currencyCode: 'iso:EUR', // The fiat currency code
    exchangeAmount: 100,     // The fiat amount that will be paid
    orderId: '123456789';    // The order ID
}

Wallet confirmation requested

When the setting walletConfirmationRequired is set to true in the init call, this event is emitted containing the following information.

Event name: btcdirect-embeddable-wallet-address-confirmation-requested

js
// event.detail:
{
    id: '123456789'; // The ID of the selected wallet
}

This ID is the ID of the provided wallet address in order to match these properly. See Provide wallet address(es) for more information.

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