Backend

The backend is the half of a system that nobody sees, so when you tap a button and something happens, the backend is what happened. It holds the records, checks the rules and answers the screen. The part you look at is the front, and the part that remembers is the back.

Think about a booking screen, where the list of free times on your phone is the front. The reason two patients cannot both take four o'clock is the backend, which takes the first request, writes it down and then tells the second person that the slot has gone. That check has to live in one place. If every screen decided for itself, a shop would sell its last item twice on a busy Friday, and someone would spend the evening apologising. A stock system like Storek works because one place owns the number rather than four screens.

Here is the part most people miss: a phone app and a browser can talk to the same backend. The receptionist works on a computer, the manager checks the same figures from a phone in the car, and a customer books from a tablet at home. All three are asking the same place, so stock, bookings and prices cannot disagree. That is why, when Linkysoft builds a web application first and adds a mobile app afterwards, the second one costs far less than the first, because the hard half is already there.

This is worth asking about before you sign anything, because some suppliers build a small separate system behind each screen. It works on delivery day, and then the phone app shows yesterday's prices, nobody can say which number is right, and the fix is a rebuild. So ask a supplier whether the website and the app read from one place, and ask what happens to your records if you change supplier next year.

You do not need to understand how any of it works, but you do need three things in writing. The data is yours, and it is backed up in a way you have watched being restored rather than only promised. You can also be given a copy in an ordinary file whenever you ask. Linkysoft puts those lines in the agreement, because a backend usually holds the only copy of things a business cannot rebuild from memory.