Connect payment API

Good afternoon
The project is a platform for collecting non-cash tips on QR.
The system is currently functioning, a payment API connection is required.
You need a specialist who can take to work in a clearly specified time.
The backend is made in PHP, a Mysql database.
Running Fastvps cloud server.
Front made on Vue, requests to the server through the axios library.
A description of the API in the attachment.