Online Payment Solutions for Every Business

Start accepting online payments with Cardknox’s robust API and suite of integrated payment acceptance tools.

From B2B to B2C, invoices to subscription services, Cardknox has the technology you need to design an online payment flow that customers love. Build a custom integration using our developer-friendly SDK and plugins, create secure forms with iFields, or get up-and-running fast with the PaymentSITE hosted checkout form.

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Cardknox API

The Cardknox API makes it easy for you to equip
online shopping carts with our advanced e-
commerce payment solutions.


Maintain full control of your payment form’s design while protecting sensitive card data and staying out of scope for PCI compliance. When iFields are used, card data is tokenized by Cardknox without ever touching the merchant’s server.

Google Pay and Apple

Grow conversions with frictionless payments at checkout. Our Apple Pay and Google Pay integrations make it easy to build e-commerce sites that cater to the new era of mobile payments.

Shopping Cart Plugins

Skip the need for extensive development work with
our plugins for leading e-commerce platforms.

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Gateway Emulators

Have an existing payment gateway integration? Cardknox gateway emulators translate your existing gateway’s API into Cardknox API so that you can process through Cardknox without any upfront development work.

PaymentSITE Hosted Checkout

Cardknox PaymentSITE is a secure and customizable online payment form that accepts credit cards, mobile wallets, ACH, and recurring payments. Whether you want to offer mobile-friendly online checkout or streamline online bill pay, PaymentSITE makes it easy.

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Advanced Security

Simplify PCI compliance, prevent fraudulent transactions, and protect your customers with Cardknox’s powerful card-not-present security features.

3-D Secure (3DS)

  • Cardknox supports EMVCo’s robust security protocol that authenticates cardholder identities in real-time.

Fraud Screening

  • Our fraud screening solution scans all incoming orders for indicators of fraud, without causing an unnecessary drop in sales.


  • Cardknox’s tokenization system encrypts sensitive data and assigns unique IDs to each transaction.

Optimize Invoicing

These valuable payment tools will help you automate online payments and save time on account reconciliations.

Split Capture

  • Perfect for wholesalers, Split Capture allows you to authorize the total order amount when a transaction is placed, and then capture multiple payments as each shipment goes out.

Recurring Payments

  • Great for subscriptions, memberships, and other repeat payments — our solution makes it easy to set up payment schedules with the desired frequency, payment method, amount, and interval.

Account Updater

  • Reduce lost sales without the hassle. Cardknox Account Updater scans customer information stored on file, identifies any expired or inactive cards, and then obtains the correct card information.

Accept Digital Wallets

Make it easy for customers to pay from their mobile devices. Cardknox’s online payment solutions support digital wallets so that shoppers can pay with just one click.
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Even More Cardknox Benefits

Competitive Rates

Cardknox’s team of pricing experts, along with our proprietary interchange qualification monitoring (IQM) technology, will ensure you get the lowest rate on every transaction. We offer a flat-rate pricing model as well as a traditional underwritten plan—and we’ll work with you to make the most cost-effective choice.

Fast Funding

We can route transactions based on each processing platform’s cutoff time, ensuring next-day funding on all credit card types, including American Express.

POS and Mobile Integrations

Create an omnichannel presence with Cardknox’s powerful payment integrations for POS systems, wireless terminals, and mobile apps.

White-Glove Support

Our in-house Customer Service and Technical Support teams are here to provide hands-on assistance with all things payments—every step of the way. Cardknox’s dedication to customer satisfaction is evident through our A+ BBB rating and 5-star Google ratings.

Get Started