KutMasterz: event ticketing with a QR code on every ticket

Overview

A ticketing platform in three parts: a storefront where buyers pick an event and pay, an Express API that generates a unique QR code per ticket and emails it, and an organizer dashboard with sales, exports and a camera-based gate scanner that validates each QR once.

The problem

The client needed ten thousand tickets generated for a single event in one go, each with its own QR, without a queue system in the stack. Generation had to finish in one request cycle without timing out, and the gate scanner had to reject a ticket the second time it was shown.

What I built

• Ticket generation in batches inside one request with per-ticket UUIDs and QR images, tuned until 10,000 tickets completed reliably without BullMQ or a worker.
• Scan endpoint that flips a ticket from valid to used atomically, so two gates scanning the same code cannot both let it through.
• Organizer dashboard: sales charts, ticket lists, ZIP export of QR images, email delivery of tickets to buyers.
• Express + Mongoose + Zod API with JWT auth; React storefront and dashboard.

Outcome

Engineering decisions

• Bulk generation without a queue
• Idempotent scan-to-used transition