Ecwid allows using any payment gateway that supports or can emulate the Authorize.Net SIM API. This feature can be used to use Ecwid with gateways it doesn't support yet or to develop custom payment modules.

Using gateways that can emulate Authorize.Net SIM

If you want to use a gateway that isn't supported yet but can emulate Authorize.Net, then still you can use it with Ecwid. 

Please perfrom these steps:

• Log in to your Ecwid control panel and open the "System Settings → Payment" page. 
• Choose the "Authorize.Net SIM" option for the "Credit card" payment method. 
• Click the "Account details" link, a pop-up will appear.
• Click the "Advanced settings" link, then change the endpoint URL to the one provided by your payment gateway. 
  
  
• Set the other fields as your payment gateway asks you to and save the changes.

After that if a customer uses the "Credit Card" method, he will use your new payment gateway. 

Custom payment gateways

If Ecwid doesn't support a payment gateway you want, you can create an integration yourself. You should create a script that will emulate the Authorize.Net SIM and act as a bridge between Ecwid and your unsupported gateway.

In a nuthshell:

• Set up Authorize.Net SIM in your Ecwid control panel, but change the endpoint to your script's URL. Important note: you don't need to have an Authorize.Net account to use other payment gateways in the "Authorize.Net emulation" mode.  
• When a customer selects this payment method, Ecwid will post the necessary order and transaction details to your script.
• Then your script should get this data and post it to the gateway you want to integrate with Ecwid. A customer finishes the transaction there and returns to your script.
• Then your script should analyze the response from your custom gateway, send it to Ecwid and return the customer to the store.

Authorize.Net SIM API docs: developer.authorize.net/guides/SIM/ (You don't need to emulate all API calls/fields there though, just the ones Ecwid uses)

If you want someone to make the integration for you, you can use this service: www.ecwid.com/connect/custom-payment-gateway-integration.html