What actually gets encoded
Not a URL. A ticket code carries an identifier that a scanning app checks against the ticket list.
- Unique per ticket, never per event, or the first screenshot admits everyone
- Opaque, so the identifier cannot be guessed by incrementing a number
- Signed where it matters, so a scanner can verify authenticity even without a live connection
- Short, because a small printed code prints and scans faster at a busy door
The mechanics of the check, including single-use enforcement and what a scanner does with a duplicate, are covered in the ticket validation explainer.
The offline question, which decides everything
At the door, the venue network is the least reliable thing in the building. A scanning setup that needs a live API call per ticket will fail exactly when it is busiest.
- Scanners should hold a local copy of the ticket list and sync afterwards
- Signed codes let a scanner accept a ticket with no connection at all
- Plan for the duplicate case explicitly: two people, one code, one seat, and a policy the door staff already know
Print and screen, both
Most tickets are shown on a phone screen now, and the two media fail differently.
- On screen: brightness matters more than size. Tell holders to raise brightness and turn off auto-dimming. Screen protectors, cracks and glare are the real causes of a stuck queue.
- On paper: 25 to 30 mm, black on white, matte. Home printers are unpredictable, so keep the code low-version and never place it near a fold or a perforation.
- On wristbands: curvature applies, so keep the code on the flattest section and oversize it.
Fraud, honestly
A printed QR code can be photographed. There is no way around that, so the defence is the validation model rather than the print:
- Single use. The second scan is rejected, which makes screenshots worthless.
- Rotating codes in a mobile wallet, refreshed every few seconds, defeat the screenshot entirely. This is why high-value events push people into an app or wallet pass.
- Name matching on premium tiers.
- Never encode a sequential ID, which turns forgery into arithmetic.
After the scan is done, the code keeps working
The ticket in someone's pocket is a channel most events waste. Once validated, the same code can open the running order, the seat map, cashless top-up, merchandise, or the post-event highlights. That is one more argument for a dynamic destination behind the validated identifier: the ticket becomes the event app without anyone downloading one.
Set up QR code ticketing in 4 steps
Encode a unique opaque identifier
One code per ticket, never per event, and never a sequential number that can be guessed.
Make the door work offline
Scanners keep a local ticket list or verify signed codes, so a collapsed venue network cannot stop entry.
Enforce single use
The second scan of a code is rejected, which is what makes a screenshot of a ticket worthless.
Keep the code useful after entry
Point the validated code at the running order, seat map or cashless top-up so the ticket replaces an event app.
Frequently asked
Can someone screenshot a QR code ticket and get in?
Only if the code is not single-use. Once the first scan marks the ticket as used, every copy of it is rejected. Rotating codes in a wallet pass remove the risk entirely.
What happens if the venue internet fails during entry?
Nothing, provided the scanners hold a local ticket list or verify signed codes offline and sync afterwards. Any system that calls an API per ticket will fail at peak.
How big should a QR code be on a printed ticket?
25 to 30 mm, black on white and matte, kept away from folds and perforations. Home printers are inconsistent, so keep the payload short and the version low.
Why do phone screens fail at the door?
Brightness, glare, cracked glass and matte screen protectors. Asking holders to raise brightness and disable auto-dimming solves most of the queue.
Should a ticket code contain the attendee name?
No. Encode an opaque identifier and let the scanner look up the details. Personal data printed into a code is readable by anyone who photographs the ticket.
Read next
Need a different QR type? Browse all 48 QR types on the home page.