How to connect offline and online store?

Question

Online shopping

Good, people.
There was a problem with the client - to completely pull out the remains in the site database and control them from any store. Those. the site serves not only as a store, but as a data server for offline stores. Now everything is at the embryonic stage and options for integrating cash registers with the site are being worked out.
Those. you need to both receive information about the balances, and send it. From the online store, I have no questions. I'm there at least [POST, GET] requests, at least through SOAP, at least through a custom API, I will screw any functionality.
But from the side of the offline store, I don’t really understand what steps to take. Maybe someone was engaged in integration and will tell you the necessary bundles of software and hardware [cash register, barcode reader, etc.]?

Answer 1

Either make all this functionality on the site, or make an api for external programs, or move the work with products into a separate service and through it receive both information for the site, and third-party ones can connect.