Why a local server
Cloud-only POS systems sync tills through the internet. That works until the connection is slow or drops, and then one till cannot see the table another till just opened. A local server keeps the shared data on a machine in the shop. The other tills talk to it over the local network, which is faster and does not depend on the internet. The server syncs with the cloud in the background.
This matters most in restaurants, where several staff work the same tables, and in busy counters, where a held order on one till may be paid on another.
Choosing and placing the server
The server till should be the most dependable machine you have: a PC rather than a tablet, on a wired connection, plugged into a UPS if power is unreliable, and set never to sleep. Put it where staff will not unplug it to charge a phone. If it restarts mid-service, the clients will wait for it to come back, so keep restarts for after close.
Reserve a fixed IP address for the server in the router's DHCP settings. Without it, a power cut can give the server a new address and the clients will not find it.
Network basics that cause most problems
All tills must be on the same local network. Guest Wi-Fi networks often isolate devices from each other, so keep tills on the staff network. Mesh systems and extenders usually work but add delay; a wired connection for fixed tills is better. If clients cannot see the server, check that they are on the same network, that the server's firewall allows the connection, and that the server's address has not changed.
When things go wrong
Write a short plan for three cases. If the internet drops, the tills keep working locally and sales upload later. If Wi-Fi drops, wired tills keep working and tablets reconnect when it returns. If the server till goes down, restart it first; if it will not come back, switch one till to standalone so you can keep selling, and reconnect after service.
Doing it in SeroPOS
Server / Client Mode in the SeroPOS app is a Pro plan feature, under Admin, then Tools. It opens Database Settings with three Database Modes: Standalone (local database only), Server (shares this till's database; Windows) and Client (connects to the server; any platform).
- On the Windows server till: choose Server. The screen shows the server's address and access token and opens a 24-hour setup window for new tills; Lock Down Now closes it early.
- On each client: choose Client. The server is found on the local network, or you enter the server IP, port 19091 and the access token, then Test Connection.
- The server restarts automatically when the PC boots.
- Client tills store their sales in the server's database. The floor plan, held orders and the kitchen display are shared.
- Each till can have its own card terminal through Admin, then Tools, then Card Terminal for This Till.
- Client tills show a status bar with Live Status; if the server is unreachable, the till shows 'Server is Offline'.