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    Checkout for OpenCart

    This guide describes how to install, configure, and use the Checkout webshop module for OpenCart 3.0.

    Compatibility: OpenCart 3.0+
    Latest version: 1.1.4 (2022-03-01)

    Before you start

    Before you start, you need an Checkout Portal account. See the guide Create account for more information about creating a free test account.


    Our OpenCart plugin is the perfect extension that enables you to use the Checkout to its full potential for your OpenCart store. Checkout supports most popular payment methods.

    You may see below all the payment methods offered by Checkout. This list refers to all markets.

    Depending on your country or region, the list may vary. If you are uncertain about a specific payment method and whether it is available in your country or region, please contact Support for more information.

    Checkout plugin - Opencart

    Apple Pay configuration for OpenCart plugin is described on the Apple Pay payment method page.

    Shop features

    • The fast checkout with "remember me" functionality.
    • Embedded checkout for an optimized user experience. Users are not redirected outside OpenCart.
    • A smart mix of payment methods to suit all preferences.
    • Multiple checkout languages and currencies for selling in your domestic market and abroad.
    • Fully syncronized payment statuses in admin order page with Checkout portal.
    • Intuitive order management with synchronized captures and refunds from admin order details page.
    • Custom webhook events for real-time payment statuses.
    • Custom Build-in debugging features.

    The following screenshot shows a checkout page provided by the Checkout module:

    Magento 1 module

    Admin panel features

    • Quick setup and flexible configuration.
    • Intuitive order management with synchronized captures and refunds.
    • Compatibility with discounts, tax (VAT), and shipping options.
    • Compatiblility OpenCart Multi-Store setups.

    The screenshot below shows the settings page for the Checkout module:

    Nets Configuration OpenCart


    Follow the step below to install the Checkout module in Opencart.

    Step 1: Install module

    You have two options when installing the Checkout module for OpenCart:

    • Alternative 1:
      1. Download the plugin archive:
      2. Extract all files to your OpenCart installation directory.
    • Alternative 2:
      1. Install modman by running the command git clone or simply copy the modman-php files into the OpenCart root directory.
      2. Install the Nets Easy module files by running the command php modman.php clone

    Step 2: Refresh Opencart Admin

    1. Navigate to Modifications in OpenCart Admin.
    2. Click the Refresh button.

    The module is now installed and ready to be configured for your Checkout account.


    After installing the module, you need to do some basic configuration of the module:

    1. Navigate to Extensions and choose the extension type Payments.
    2. Locate the Checkout module and press the Edit button to access the configuration.
    3. Fill out the required fields, such as merchant ID and integration keys (secret keys and checkout keys).
    4. (Optional) Customize the module according to your needs using the additional settings on the configuration page.

    Both the merchant ID and the integration keys can be found in Checkout Portal. See the following pages for more help:

    The screenshot below shows the configuration page for the module:

    Nets Configuration OpenCart

    The following table lists all the settings you can configure in the administration area for the Checkout module:

    Configuration settingDescription
    Secret key (Live)Your live secret key from Checkout Portal.
    Checkout key (Live)Your live checkout key from Checkout Portal.
    Secret key (Test)Your secret key for test purchases from Checkout Portal.
    Checkout key (Test)Your checkout key for test purchases from Checkout Portal.
    Order StatusThe status that new orders will be assigned when placed through Checkout.
    Terms & conditionsThe URL to the terms and conditions of your webshop.
    Merchant Terms & conditionsThe URL to the privacy and cookie settings of your webshop.
    Allowed customer typesConfigures which customer types should be accepted on the checkout page. B2C means private customers (Business-to-Consumer). B2B means business customers (Business-to-Business).
    TestToggles between test mode (Enabled) and live mode (Disabled). Choose test mode if you want to make test purchases using the test environment. There are sample card numbers and invoice addresses for testing purposes. Live mode requires an approved account.


    You've now installed and configured the Checkout webshop module. If you have further questions, please see the troubleshooting section below or reach out to our support.

    Order management

    Orders placed using Checkout can be managed in the Checkout portal. There you can charge, refund, or cancel payments. 

    It's also possible to view the status of orders placed using Checkout directly in OpenCart Admin by navigating to Sales > Orders.

    All transactions performed by Nexi Group are accessible in Checkout Portal.

    Orders Listing Screen OpenCart 3.0


    Below are some of the most common configuration errors, their cause and steps that you can follow to solve them.

    Nexi Group payment plugin is not visible as a payment method

    • Ensure the Nets plugin is available under Extensions > Payments in the extensions configuration.
    • Temporarily switch to the OpenCart 3 standard template. Custom templates might need additional changes to ensure correct display. Consult with your web designer or developer.

    Nexi Group payment window is blank

    • Ensure your integration keys in the Nexi Group plugin settings are correct and do not contain additional blank spaces.
    • Temporarily deactivate third party plugins that might affect the functionality of the plugin.
    • Check if there are any temporary technical inconsistencies:

    Payments in live mode don't work

    • Ensure you have an approved Live Checkout account for production.
    • Ensure your Live Checkout account is approved for payments with the selected currency.
    • Ensure payment method data is correct and supported by your Checkout agreement.

    Go live checklist

    For more information, refer to the section Go-live checklist.

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