Why a ticket cannot be a static QR code
A static QR code contains the same text for every attendee. If you use it as a ticket, forwarding the image is enough for ten people to get in with the same code. For real control you need a unique identifier per ticket, issued by a ticketing platform, and a scanner that marks each code as used.
That identifier is usually a URL with a token: https://tudominio.com/t/ABC123. The gate opens the URL or queries an API, verifies the token and logs the check-in. If you have no platform, a static QR code works only as an informational invitation, not as access control.
What to look for in a gate scanner
- Offline mode: the code list must be downloadable before the event; coverage inside a hall is not reliable.
- Single validation: the second scan must be rejected or flagged as “already used”.
- Speed: a queue of 200 people needs scanners that respond in less than a second.
- Logging: time and gate for each entry to resolve incidents.
- Staff: someone who can validate a ticket manually if the attendee's phone fails.
Static QR codes that do add value
There are uses where the same code for everyone is correct: the event program, the venue map, guest Wi-Fi, the feedback form, the photo album or the playlist. Place them at several points with clear text. For the album, check the permissions: an “anyone with the link can edit” link can end with photos deleted.
Signage: a QR code to be read at 3 meters needs about 30 cm per side. If the attendee has to walk closer, the poster is badly sized and a queue will form.
Badges and wristbands
At trade shows and concerts, the QR badge is printed on the credential itself or linked to a wristband. The code must be unique, tied to a person and revocable if lost. Do not print readable personal data next to the code: the QR already contains the token and the credential is worn in plain sight.
For small events, a guest list with one code per person and a phone with a camera may be enough. For thousands of attendees, you need a ticketing platform; the QR code is only the interface.
Frequently asked questions
One QR code for all tickets?
Not for access control; yes for information, Wi-Fi or the program.
What do I need at the gate?
A code list, offline scanning and a used mark.
How do I share photos?
With a QR code to an album with reviewed permissions and a privacy notice.
What size for a poster?
About 30 cm per side to read at 3 meters; 5–8 cm at a counter.