Important information

The API reference is now available here.
The deprecated API reference is available here.


Accept Unzer Direct Debit with UI components

Use Unzer UI component to add Unzer Direct Debit payment to your checkout page.


Using UI components for Unzer Direct Debit you get a ready-made form with the fields necessary to make this type of payment. You can check a demo version of the component here. Basic steps for integrating using UI components are the same for all payment methods and you can read about them here.

Before you begin

Step 1: Add UI components to your payment page
client side

First, you need to initiate our UI components library and add the payment form to your payment page.

Initiate UI component

Load our JS script and CSS stylesheet

Include Unzer’s script and stylesheet on your website.

Always load the script and stylesheet directly from Unzer:

<link rel="stylesheet" href="" />
<script type="text/javascript" src=""></script>
Faster load time
To make your website load faster, insert JavaScript scripts at the bottom of your HTML document.
Importing Unzer styles
To minimize the risk of Unzer styles affecting the styles of your webpage, we suggest putting unzer.css on top of other imported CSS files.

Create an Unzer instance

Create an unzer instance with your public key:

// Creating an unzer instance with your public key
var unzerInstance = new unzer('s-pub-xxxxxxxxxx');
Placeholder keys
In the previous example, we used a placeholder API key for example purposes. You should replace it with your public key.

Localization and languages

We support localization with locale option parameters. Check the Localization page for a list of all the supported locales.

The auto option (applied by default) uses the client’s browser language.

Here you can see how to set the language, in our case ‘de-DE’ - to do so, add a comma separated parameter to your unzer instance:

// Creating an unzer instance with your public key
var unzerInstance = new unzer('s-pub-xxxxxxxxxx', {locale: 'de-DE'});

Implement the payment form

To securely collect payment data from your customer, you need to create a payment form with empty DOM elements and unique ID’s within them. That way unzer.js will know where to place its UI components.

<form id="payment-form" class="unzerUI form" novalidate>
    <div id="sepa-IBAN" class="field">
        <!-- The IBAN field UI Element will be inserted here -->
    <button class="unzerUI primary button fluid" id="submit-button" type="submit">Pay</button>
    <!-- You can add the required SEPA mandate text here -->

Matching IDs

When choosing your ID for a UI component, make sure that the names in your HTML and JavaScript match.

For example:

<div id="sepa-IBAN"> matches containerId: "sepa-IBAN".

SEPA mandate

Unzer Direct Debit payment method requires an approval of SEPA mandate by the customer. Below you can see sample mandate text you can use on your page.

SEPA mandate sample: English textSEPA mandate sample: German text
SEPA Direct Debit Mandate

By signing this mandate form, you authorize {NAME OF MERCHANT} to send instructions to your bank to debit your account and your bank to debit your account in accordance with the instructions from {NAME OF MERCHANT}.

Note: As part of your rights, you are entitled to a refund from your bank under the terms and conditions of your agreement with your bank. A refund must be claimed within 8 weeks starting from the date on which your account was debited. Your rights regarding this SEPA mandate are explained in a statement that you can obtain from your bank.

In case of refusal or rejection of direct debit payment I instruct my bank irrevocably to inform {NAME OF MERCHANT} or any third party upon request about my name, address and date of birth.
SEPA Lastschrift-Mandat (Bankeinzug)

Ich ermächtige {NAME OF MERCHANT}, Zahlungen von meinem Konto mittels SEPA Lastschrift einzuziehen. Zugleich weise ich mein Kreditinstitut an, die von {NAME OF MERCHANT} auf mein Konto gezogenen SEPA Lastschriften einzulösen.

Hinweis: Ich kann innerhalb von acht Wochen, beginnend mit dem Belastungsdatum, die Erstattung des belasteten Betrags verlangen. Es gelten dabei die mit meinem Kreditinstitut vereinbarten Bedingungen.

Für den Fall der Nichteinlösung der Lastschriften oder des Widerspruchs gegen die Lastschriften weise ich meine Bank unwiderruflich an, {NAME OF MERCHANT} oder Dritten auf Anforderung meinen Namen, Adresse und Geburtsdatum vollständig mitzuteilen.

Create a payment type resource

Call the method unzerInstance.SepaDirectDebit() to create an instance of the Payment Type Unzer Direct Debit.

// Creating an Unzer Direct Debit instance
var directDebit = unzerInstance.SepaDirectDebit()

// Rendering the input field
directDebit.create('sepa-direct-debit', {
  containerId: 'sepa-IBAN'

Add an event listener for “submit” of the form.

Inside, create a Promise on the SepaDirectDebit object. The Promise gets either resolved or rejected:

let form = document.getElementById('payment-form');
form.addEventListener('submit', function(event) {

        .then(function(result) {
            // Submit the ID of the created payment type to your
            // backend to perform the payment transaction with it.
            typeId =;
        .catch(function(error) {
            // handle errors
            document.getElementById('error-holder').innerText = error.customerMessage || error.message || 'Error'

Optional: Customize UI components

You can easily customize the font of the form by changing the options within the create method. Here you can set the following styles: fontSize, fontColor and fontFamily.

Sepa.create('sepa-direct-debit', {
    containerId: 'sepa-IBAN',
    fontSize: '16px',
    fontColor: 'lightgrey',
    fontFamily: 'Arial, Helvetica, sans-serif'

Step 2: Make a payment
server side

Make a charge transaction

Now, make a charge transaction with the SepaDirectDebit typeId that you created in the frontend. With a successful charge transaction money is transferred from the customer to the merchant and a payment resource is created.

  "amount": "20",
  "currency": "EUR",
  "resources": {
      "typeId": "s-sdd-zquetx73qvpm"
$unzer = new Unzer('s-priv-xxxxxxxxxx');
$sepa-direct-debit = $unzer->fetchPaymentType('s-sdd-zquetx73qvpm');
$charge = $sepa-direct-debit->charge(20.0, 'EUR');
Unzer unzer = new Unzer("s-priv-xxxxxxxxxx");
Charge charge = unzer.charge(BigDecimal.ONE, Currency.getInstance("EUR"), "s-sdd-zquetx73qvpm");

The response looks similar to the following example:

    "id": "s-chg-1",
    "isSuccess": true,
    "isPending": false,
    "isError": false,
    "message": {
        "code": "COR.000.100.112",
        "merchant": "Request successfully processed in 'Merchant in Connector Test Mode'",
        "customer": "Your payments have been successfully processed in sandbox mode."
    "amount": "20.0000",
    "currency": "EUR",
    "returnUrl": "",
    "date": "2021-05-10 15:29:09",
    "resources": {
        "paymentId": "s-pay-133634",
        "traceId": "bbaeefa04492a6bd033845de78b1f774",
        "typeId": "s-sdd-zquetx73qvpm"
    "paymentReference": "",
    "processing": {
        "creatorId": "13213213344324324",
        "identification": "4851.9174.9801",
        "iban": "DE89*************3000",
        "bic": "CO******XX",
        "uniqueId": "31HA07BC813E8DE2B6D6096556538A37",
        "shortId": "4851.9174.9801",
        "traceId": "bbaeefa04492a6bd033845de78b1f774"

For a full description of the charge transaction, refer to the relevant server-side integration documentation page: Charge a payment (direct API calls), Charge a payment (PHP SDK), Charge a payment (Java SDK).

Step 3: Check status of the payment
server side

Once the customer is redirected to the returnUrl, you can fetch the payment details from the API, by using the resources.paymentId from the charge response above to handle the payment according to its status. If the status of the payment is completed , the payment process has been finished successfully and can be considered as paid. Check all possible payment states here.


  "id": "s-pay-xxxx",
  "state": {
    "id": 1,
    "name": "completed"
  "amount": {
    "total": "119.0000",
    "charged": "119.0000",
    "canceled": "0.0000",
    "remaining": "0.0000"
  "currency": "EUR",
  "orderId": "My Order Id",
  "invoiceId": "",
  "resources": {
    "customerId": "",
    "paymentId": "s-pay-xxxx",
    "basketId": "",
    "metadataId": "",
    "payPageId": "",
    "traceId": "e4c4fb1c81d2167eb86eb5a68cfb7760",
    "typeId": "s-sdd-xxxxxxxxxxx"
  "transactions": [
      "date": "2021-05-27 11:45:46",
      "type": "charge",
      "status": "success",
      "url": "",
      "amount": "119.0000"

Step 4: Display the payment result
client side

Use the information from the Check status of the payment step to display the payment result to your customer.
This can be the success or error page of your shop. If something went wrong, you can use the client message from the API response and show it to the customer.

Manage payment
server side

For more details on managing Unzer Direct Debit payments, such as refunding them, see Manage Unzer Direct Debit payments


We recommend subscribing to the payment event to receive notifications about any changes to the payment resource. As soon as the event is triggered you should fetch the payment and update the order status in your shop according to its status.


For more details on implementing webhooks to receive notifications, see Notifications page.

Error handling

All requests to the API can result in an error that should be handled. Refer to the Error handling guide to learn more about Unzer API (and other) errors and handling them.

Test & go live

You should always test your integration before going live. First perform test transactions using test data. Next, check against Integration checklist and Go-live checklist to make sure the integration is complete and you’re ready to go live.

See also