QR code for a free ticket — how to, with no printer and no dedicated app

A QR code is just an image encoding a string of text (here, a unique identifier pointing to your registration). It contains no personal data and no sensitive info — just a random ID telling the event 'this ID matches registration #1547'. The scan opens the ID on the server: the platform checks that the registration exists, that it hasn't been scanned (anti-duplicate), and marks the person as 'present' with a timestamp. All in under 200 ms. On the visitor side, they receive the QR code by email — they show it on their phone at the door. No need to print.

Most platforms force a dedicated app on you. On JustOneEvent, the scanner is a web page (PWA) that runs in Chrome, Safari or Firefox on a phone — add it to the home screen for one-tap access. 3 conditions: — Recent smartphone (rear camera, 2018+) — Network connection (4G or Wi-Fi at the door) — JustOneEvent account logged in with organiser access to the event (the scanner is on the event page in the dashboard) The PWA also runs in degraded offline mode — scans are stored locally and sync when the network returns. Handy in a basement / forest / cellar.

1. The QR code sent via WhatsApp no longer works WhatsApp recompresses images: the QR becomes blurry and stops scanning. Always send the QR by email (PNG/JPG without recompression). 2. A 2-person seat with the same QR 1 QR = 1 registration. If Sophie signs up Jean as a '+1', generate 2 distinct registrations. Otherwise the second person arrives and the scan says 'already used'. 3. No backup plan in case of failure Keep the CSV export of the list on an offline phone. If the web scanner falls over, you can verify by name. Not ideal but better than blocking 80 people at the door.

For a free event, no. The 'someone forwards their QR to a friend' fraud exists but is marginal: the person can only enter once (server-side anti-duplicate), so the forwarded QR at best replaces the legitimate registrant — who is free, so the harm is zero. For a paid or high-value event (gala, fundraiser), the simple measure: identity check at scan. The organiser shows the registrant's name after the scan and compares it against a physical ID document. Manual but effective. In 95% of cases, the standard QR is enough.