Use Cases

QR Codes for Event Check-In & Ticketing

Ticketing is one of the more technically demanding QR code use cases, because the requirements go beyond "does it scan." Each ticket needs a unique code, the check-in process needs to be fast enough not to create a bottleneck at the door, and the system needs some way to prevent the same code from being used twice — whether that's an honest duplicate ticket sent to friends or an actual counterfeiting attempt.

Every ticket needs a unique code

Unlike a menu or business card, where one code serves everyone, a ticketing QR code has to be generated individually per attendee — usually encoding a unique ticket ID or token rather than any human-readable information. That ID gets looked up against a database at check-in to confirm validity, rather than the code itself carrying meaningful data. This is a fundamentally different architecture than a "print one code, use it everywhere" case, and it's why most events use a dedicated ticketing platform rather than a general-purpose QR generator for this specific piece.

Preventing duplicate use

Because a QR code image can be screenshotted and forwarded trivially, most ticketing systems don't rely on code secrecy alone. Two common approaches:

One-time validation. The check-in system marks a ticket ID as "used" the instant it's scanned. A second scan attempt of the same code — whether from a duplicate screenshot or an honest mistake — gets flagged immediately rather than let through.
Rotating or time-limited codes. Some higher-security events (large concerts, conferences with paid tiers) use codes that regenerate periodically inside an app, so a static screenshot goes stale before it can be reused. This adds real complexity and generally requires a dedicated ticketing platform rather than a simple static QR code.

For most small-to-mid-size events — meetups, community fundraisers, local conferences — one-time validation against a database is more than sufficient, and dramatically simpler to implement than rotating codes.

Design for speed at the door

Check-in lines create real time pressure, and a code that's slow to scan compounds quickly across hundreds of attendees. Practical guidance:

Use at least M level error correction — see our error correction guide — since tickets are often displayed on phone screens at varying brightness, sometimes with screen protectors or cracked glass affecting scan quality.
Print or display the code large enough to scan on the first attempt — undersized codes on a printed ticket are a common source of door-line slowdowns.
If using phone-displayed tickets, remind attendees in advance to turn brightness up, since scanning a dim screen in bright outdoor light is a frequent point of friction.