This is a roughed-out example Offsite Payment Gateway that integrates with Drupal 8 Commerce 2.x.
This gives you an idea of how an offiste payment module can look. This particular module is for an offsite payment gateway that where a user may or may not return. You'll be able to see in onNotify() that the saving of the order/payment needs to happen there.
- Drupal 8.x
- Drupal Commerce 2.x
Do you need help with customizing your offsite payment gateway? Create an issue and describe the problem you're having.
Do check the Drupal Commerce Documentation every so often as they are actively being updated. They have more examples this year (2019) than previous years.
MIT License