Install:
apt-get update
apt-get install splynx-paypal
Configuration required: /var/www/splynx/addons/splynx-paypal/config/params.php
// Splynx url (without last slash)
'splynx_url' => '',
// PayPal credentials
// You can get it by creating REST API app on page "My Apps & Credentials" in PayPal developer
// account (https://developer.paypal.com/developer/applications/)
'clientId' => '',
'clientSecret' => '',
'isProduction' => true,
'currency' => 'USD',
Manual with video: PayPal payments in Splynx
Screenshot: