Case · Two-day event · General admission
QR tickets and a check‑in that worked offline
The event needed a QR ticket for every attendee, a way to check them in at the door without the venue's wifi and, afterwards, certificates. I built the whole flow.
DatesSep 6–7, 2026
Attendees318
Doors1
Phones6
Admit one
Valid ticket · row C
main door · offlinesample data
212/ 318 attendees
| phones scanning | 6 |
| last check-in | Lucía M. · row F |
| venue signal | not needed |
318attendees across 4 ticket types
305tickets delivered by email without a bounce
6phones scanning at one door
237certificates delivered afterwards
The challenge
Messy dataThe list came from a spreadsheet with empty headers, two emails in one cell and invisible characters pasted from Word.
An unknown venueSix people at a single entrance, with phones nobody knew in advance and no guaranteed data or wifi.
Hundreds of personal filesEvery ticket and certificate had to reach the right person, with a record of who did not get it and why.
The flow
● doneSpreadsheet
● doneClean data
● doneQR tickets
● doneEmail
● doneOffline check-in
● doneCertificates
What I built
Data cleanupOne clean record per attendee, with four ticket types and an email for each.
Tickets and sendingThe designer's template, the attendee's name and a unique QR on every ticket. Sending retries on its own and every undelivered ticket keeps its reason.
Check-in appInstalls on any phone and keeps working without signal. Scans the QR, searches by name and exports each check-in time.
Certificates and reportsCertificates matched to each attendee and PDF reports for the organizer.
The app at the door
screenshots with sample attendees
305 of 318 tickets reached the inbox without a bounce. At the door, six phones scanned offline and the venue's signal never held up the line.