Ticket validation on handheld terminals

The problem

Not every entrance has a turnstile: garden and section entrances, event areas, group entries and times when a turnstile is under maintenance. Tickets still had to be validated through the system at these points.

My role

Sole developer: React Native mobile app, the API side, field testing and go-live.

The solution

The handheld terminal uses the same central API as the turnstiles. Staff scan the QR code, the ticket is validated and the result is clear at a glance: valid or invalid. Scans land in the same pool as turnstile entries, so reports do not treat them as a separate channel.

Outcome

• Entrances without turnstiles joined the same validation and reporting flow.

Decisions I made

• The same rules as the turnstiles: the terminal carries no validation logic of its own; it uses the same central API. Rules change in one place.
• The result at a glance: at a busy entrance staff have no time to read. The result is large, coloured and a single word: valid or invalid.
• One pool of data: handheld scans land in the same records as turnstile entries, so the visitor count and reports stay correct whatever the entry type.
• React Native: building and maintaining one codebase mattered a great deal on a project run by a single developer.

Technologies

• Mobile: React Native
• Backend: C#, .NET, REST API
• Database: SQL Server
• Hardware: Android handheld terminal