Payment system and database entry?

Question

OctoberCMS

I use October. An order page has been created, where all information is collected. Began to bind the payment system. To use it, you need to send a POST request with the amount to their server.
Question: how to simultaneously implement and write the necessary data to the database on one page and then redirect it to the payment system?
As I understood from the examples, in October, only AJAX is used when processing forms, how from onOrder() - AJAX functions will redirect to the payment system?
PS method="POST" action="..." work, but then you can't write data to the database

Answer 1

It's a bad idea to do it on one page at once.
That's right - first you fix the order in the database (including getting its identifier, which the payment system will already refer to when it notifies you of the payment)
And why are you only sending the data to the payment system.

Answer 2

What solution do you use to implement the store?