Different constraints entirely
A kiosk is used once, briefly, by someone with no training, no login and no patience, standing up, possibly in a queue. It must also survive being unattended for days.
That combination changes almost every design decision from ordinary application development.
Interface rules
- Large targets, high contrast, readable from standing distance
- One decision per screen, with a visible way back
- No typing where selection will do
- Automatic reset to the start after inactivity, clearing any personal data
- Accessible to wheelchair users and people with visual impairments, which is both right and frequently a legal requirement
The inactivity reset is the one that gets missed. Someone walks away mid-transaction and the next person sees their details. That is a data incident caused by a missing timer.
Unattended reliability
- Restart cleanly and return to the kiosk application automatically
- Recover from network loss without a person intervening
- Prevent exit to the operating system — kiosk mode properly configured
- Handle peripheral failure gracefully: a jammed printer should not stop the whole transaction
- Log everything, because you cannot ask the user what happened
Remote management is essential
You need to see whether each terminal is online, what version it runs, whether the printer has paper and whether anything is failing — without visiting the site.
Deploying updates remotely, with the ability to roll back, is equally important. Sending someone to twelve sites to fix a bad release is the scenario to design against.
Plan for the physical
Screen brightness in changing light, mounting height, cable security, ventilation, and what happens when someone spills a drink on it. These affect the software: brightness affects contrast choices, mounting affects reach.
Visit the location before designing. Kiosks designed from a floor plan reliably encounter a pillar nobody mentioned.
Cost
Software for a straightforward kiosk application typically £20,000–£50,000 including remote management. Hardware, mounting and installation are separate and vary enormously.
The remote management piece is frequently cut to save money and is the part that determines running cost.