https://github.com/orzfly/opencart-gateway-ripple
opencart-gateway-ripple
This extension allows you to accept payments in OpenCart via Ripple.com.

supports all currencies;
updates order status from public ripple ledger over JSON-RPC;
redirects user to their Ripple wallet //send URL;
creates invoices / sends invoice email upon payment confirmation;
shows Ripple transaction in Order History;
configure RPC SSL, user, pass, host, port;
use Cron jobs to check transactions every 15 minutes;
Usage

Download this plugins and unzip into OpenCart's directory.
Enable this plugin in OpenCart admin panel.
Set up cron jobs.