Hi.

Is there a way to identify that the customer has already made the payment through a payment method (which I implemented myself)?

I can think of a console application that consumes an API and checks the payment status of the order. And according to the state, update the payment status of the order in GrandNode.

Or does the system have an easier option for this type of case?

It's used just to filter? Or it has to be something more sophisticated? If not, you can filter orders by payment status.

I use it to synchronize the status of system orders based on the status of payment in the API.

But I solved the problem by creating a Task https://docs.grandnode.com/tasks

Ah ok. Now I understand the purpose :) I'm happy that it's solved.