Important information

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


[Deprecated] Unzer Installment

Learn more about Unzer Installment and its workflow

Unzer installment is a popular payment method both for merchants and their customers especially for larger basket sizes. The merchant ships their goods and the customer pays their order via direct debit once the goods arrived in small installments. Unzer offers to check for received funds and commences matching. Unzer will buy the entire claim and pay the full amount to the merchant upon the shipping call.

Additionally, Unzer will also send payment reminders to the customer if they don’t pay in a predefined time frame. If the end customer does not pay after they received the final then the claim is handed over to a debt collector.

Available inSupported currenciesRedirectRefundPartial RefundReversalChargebackRecurringPayoutPay laterUnzer Secured
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Unzer Installment is only available with basket v1.


  • Ease of use: The customer can easily step through the checkout and choose the number of installments in which they want to pay for the goods. They provide their bank account details and the installments will be debited from their account via SEPA direct debit.
  • High level of security: Unzer is addressing the usual danger with installment payments. If the transaction was successful and the shipment transaction has been sent in time, you will receive the funds even if the customer doesn’t send the payment.
  • Preferred payment method for large baskets: The customer can buy higher baskets and pay it in smaller installments over a longer period of time.

Payment workflow

The following diagram explains workflow for Unzer invoice-secured payments.

Unzer Installment workflow

Step 1: Get available installment plans.

After your customer chooses to pay in Installment, you need to show them all available Installment plans. To fetch all Installment plans for a specific (total) amount, you must make a GET call.

Step 2: Create customer and basket resources.

Unzer Installment requires additional information about the customer and the basket. The baskets resource contains all product information needed for the requested transaction.

Step 3: Create a installment-secured payment type resource.

A resource ID is generated in the response and is used in the workflow to complete the payment.

Step 4: Make an authorize transaction with the installment-secured resource that you created.

With Unzer Installment, you can’t charge the customer directly. You need to authorize the full amount first.

Step 5: Make an empty charges transaction with the installment-secured resource that you created.

Step 6: After the transaction, display the result (mainly contains the payment information) to the customer in the front end of the online shop.

Step 7: Add payment details on invoice


Step 8: After the goods are shipped, a shipment call must be placed to activate the factoring.

Integration options

Quickly integrate with Unzer without any programming knowledge

Use pre-built, configurable all-in-one pages with your own mix of payment methods

Use pre-built forms and quickly integrate with minimum work on the client side

Integrate with Unzer using your own payment form