CartModules: Unzer Payment Gateway for CS-Cart

Accept payments across Europe with Unzer (formerly Heidelpay)

Integrate Unzer, one of Germany's leading payment service providers, with your CS-Cart or Multi-Vendor store. This addon uses the Unzer Hosted Payment Page (HPP) for a secure, PCI SAQ A compliant checkout experience. Customers are redirected to Unzer's hosted page where they can pay with cards, SEPA, PayPal, Sofort, Giropay, iDEAL, and many more European payment methods — all through a single integration.

Key Features

• Dual Checkout Modes — Choose between redirect (hosted page) or inline (embedded UI Components) checkout
• On-Site Payment — Inline mode keeps customers on your store during payment
• Apple Pay — Accept Apple Pay payments via inline checkout
• Google Pay — Accept Google Pay payments via inline checkout
• Hosted Payment Page (HPP) — PCI SAQ A compliant. No card data touches your server.
• Charge & Authorize — Choose between immediate capture or authorize-then-capture workflows.
• 3D Secure 2.0 — Built-in support for Strong Customer Authentication (SCA) as required by PSD2.
• Multi-currency — EUR, CHF, GBP, PLN, DKK, NOK, SEK, CZK.
• EU-wide coverage — Germany, Austria, Switzerland, and all EU member states.
• Flexible status mapping — Map Unzer payment outcomes (approved, pending, failed) to any CS-Cart order status.
• Server-to-server notifications — Reliable payment confirmation even if the customer closes their browser.
• Idempotent callbacks — Duplicate notifications are safely ignored.
• Detailed logging — All payment events logged via CS-Cart's built-in log system with sensitive data automatically stripped.
• Zero configuration for environment — Sandbox and production use the same API endpoint. Your key prefix (s-priv vs p-priv) determines the mode.

Supported Payment Methods (via Unzer HPP)

• Visa, Mastercard, American Express
• SEPA Direct Debit
• PayPal
• Sofort / Klarna
• Giropay
• iDEAL
• EPS
• Bancontact
• Przelewy24
• And more via the Unzer HPP

Checkout Modes

• Redirect (Default) — Customer is redirected to Unzer's secure hosted payment page
• Inline (Embedded) — Unzer UI Components renders an embedded payment form directly on your checkout page. Customer pays without leaving your store.

How It Works

1. Customer selects Unzer at checkout and clicks "Place order".
2. They are redirected to the Unzer Hosted Payment Page (or inline form appears on checkout page).
3. Customer chooses a payment method and completes payment (with 3D Secure if required).
4. Customer is redirected back to your store.
5. The addon verifies the payment with Unzer and updates the order status.

Requirements

• CS-Cart or Multi-Vendor 4.x
• PHP 7.1+
• SSL certificate (HTTPS)
• Unzer merchant account (www.unzer.com)

Installation

1. Go to Add-ons > Manage add-ons, click Manual installation, and upload the addon zip
2. Activate the addon and enter the license key
3. Create a new payment method under Administration > Payment methods.
4. Select "Unzer Payment Gateway" as the processor.
5. Enter your Unzer private key and public key.
6. Configure your preferred currency and order status mappings.
7. Save and you are ready to accept payments.

Security

• PCI SAQ A compliant — all card data handled by Unzer.
• SSL verification enforced on all API communications.
• Sensitive credentials never written to logs.
• All database queries use parameterized placeholders.
• All user input is sanitized (type-cast and trimmed).

Compatibility