Accept EPS with server-side-only integration

Build your own payment form to add EPS payment to your checkout page.

Overview

EPS doesn’t require any input from the customer on the merchant website. The customer must be redirected to EPS to provide the required information to process the transaction. After that, the customer is redirected back to the merchants website displaying the payment. Optionally, you can include a bank selection for the customer to pre-select their bank before you redirect the customer (see list of supported banks or BICs section).

You can see an example of EPS bank selection component on our demo page.

Before you begin

• Check the basic integration requirements.
• Familiarize yourself with the general Server-side-only integration guide.

Step 1: Create a payment type resource

server side

Data for the EPS payment:

Banks supported by EPS:

When creating the payment type EPS, you need to send a request to the Unzer API. The response contains an id , this is later referred to as typeId. You require this typeId to perform the transaction. As mentioned previously, bic is optional.

POST https://api.unzer.com/v1/types/eps

{
  "bic":"STZZATWWXXX"
}

// get the BIC from your payment form.
$unzer = new Unzer('s-priv-xxxxxxxxxx', SupportedLocale::GERMAN_GERMAN);
$eps = $unzer->createPaymentType((new EPS())->setBic($bic));

// get the BIC from your payment form.
Unzer unzerInstance = new Unzer("s-priv-xxxxxxxxxx");
EPS eps = unzerInstance.createPaymentType(new EPS(bic));

The response looks similar to the following example:

{
  "id": "s-eps-9rxdhskuhnea",
  "method": "EPS",
  "recurring": false,
  "geoLocation": {
    "clientIp": "127.0.0.1",
    "countryCode": "DE"
  },
  "bic": "STZZATWWXXX"
}

For a full description of EPS payment type creation, check API reference.

Step 2: Make a payment

server side

Make a charge transaction

Now, make a charge transaction with the EPS typeId that you created and the returnUrl leading back to your shop after the payment is completed on the external page. With the charge transaction an amount is requested but is not yet transferred. Initially the transaction will be pending and a payment resource is created.

POST https://api.unzer.com/v1/payments/charges
   
Body:
{
  "amount" : "20",
  "currency": "EUR",
  "returnUrl": "https://www.my-shop-url.de/returnhandler",
  "resources" : {
    "typeId" : "s-eps-jldsmlmiprwe"
  }
}

$unzer = new Unzer('s-priv-xxxxxxxxxx');
$eps = $unzer->fetchPaymentType('s-eps-0ajzmaxcuvhc');
$charge = $eps->charge(20.0, 'EUR', 'https://www.my-shop-url.de/returnhandler');

Unzer unzer = new Unzer("s-priv-xxxxxxxxxx");
Charge charge = unzer.charge(BigDecimal.ONE, Currency.getInstance("EUR"), "s-eps-0ajzmaxcuvhc", new URL("https://www.my-shop-url.de/returnhandler"));

The response looks similar to the following example:

{
    "id": "s-chg-1",
    "isSuccess": false,
    "isPending": true,
    "isError": false,
    "redirectUrl": "https://payment.unzer.com/v1/redirect/eps/s-sGYdGywWpxzW",
    "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": "https://www.my-shop-url.de/returnhandler",
    "date": "2021-05-10 00:51:03",
    "resources": {
        "paymentId": "s-pay-131937",
        "traceId": "70ddf3152a798c554d9751a6d77812ae",
        "typeId": "s-eps-jldsmlmiprwe"
    },
    "paymentReference": "",
    "processing": {
        "uniqueId": "31HA07BC8157BD2BC04D483EFA914465",
        "shortId": "4845.3426.1987",
        "traceId": "70ddf3152a798c554d9751a6d77812ae"
    }
}

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).

Forward the customer to the external payment page

After you charge the EPS resource, implement the following flow:

1. Forward the customer to the redirectUrl returned in the response to your charge request.
2. The customer is forwarded to the EPS payment page.
3. After a successful payment or abort on the EPS page, the customer is redirected to the returnURL specified in the initial charge call.

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.

GET https://api.unzer.com/v1/payments/{payment_ID}

{
    "id": "s-pay-131937",
    "state": {
        "id": 1,
        "name": "completed"
    },
    "amount": {
        "total": "20.0000",
        "charged": "20.0000",
        "canceled": "0.0000",
        "remaining": "0.0000"
    },
    "currency": "EUR",
    "orderId": "",
    "invoiceId": "",
    "resources": {
        "customerId": "",
        "paymentId": "s-pay-131937",
        "basketId": "",
        "metadataId": "",
        "payPageId": "",
        "traceId": "70ddf3152a798c554d9751a6d77812ae",
        "typeId": "s-eps-grpucjmy5zrk"
    },
    "transactions": [
        {
            "date": "2021-05-10 00:51:03",
            "type": "charge",
            "status": "success",
            "url": "https://api.unzer.com/v1/payments/s-pay-131937/charges/s-chg-1",
            "amount": "20.0000"
        }
    ]
}

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 EPS payments, such as refunding them, see Manage EPS payments.

Notifications

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.

  {
    "event":"payment.pending",
    "publicKey":"s-pub-xxxxxxxxxx",
    "retrieveUrl":"https://api.unzer.com/v1/payments/s-pay-774",
    "paymentId":"s-pay-774"
  }

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

• Manage API resources:
  • Manage API resources (direct API calls)
  • Manage API resources (PHP SDK)
  • Manage API resources (Java SDK)
• Unzer API basics