Events are the one environment where QR codes are unavoidable and also most likely to fail — because the venue is exactly where mobile connectivity collapses.
Two thousand people in a hall are two thousand phones on one or two cell sites. Anything requiring a page load at the door will be slow when it matters most. Designing around that is most of the work.
The connectivity rule
Must work offline: entry tickets, calendar entries, contact exchange, venue Wi-Fi, emergency information. Encode the data directly so no network is needed. A calendar QR carries the whole event in the pattern.
Can require a connection: agenda, speaker profiles, feedback forms, slide downloads, sponsor offers. These are consumed while seated, when there is time to wait.
Getting this backwards is the classic event failure: a dynamic ticket code at the entrance, a queue forming, staff falling back to checking names on a laptop.
Before the event
On the invitation: a calendar code. An encoded event contains title, date, time, location and description. One scan puts it in the calendar with no typing and no signup. The highest-value code of the whole event, because it directly reduces no-shows — and needs no network.
Include the venue address in the location field. Most calendar apps make it tappable for navigation, removing the "where was it again" message on the morning.
On posters and flyers: registration. Use a dynamic code. Registration URLs change, sessions sell out, pages move. A poster printed six weeks out will outlive at least one URL change. Give each poster location its own code so you learn which venue produced signups.
At the door
Tickets: encode the ticket data itself. Never a link. The entrance is where the network is worst and the queue most visible.
Print size at least 3 cm. Attendees show tickets on cracked screens at low brightness with auto-dimming on. Larger is more forgiving.
Error correction Q or H. Tickets get folded, wet and crumpled.
Test scanning from a screen, not just paper. Glossy phone screens under venue lighting behave differently from card.
Have a manual fallback. A readable reference number beside the code. Some phone will be dead.
Venue Wi-Fi: encode the credentials. Network name and password in the pattern. Removes a question staff would otherwise answer several hundred times.
During the event
Agenda and session details. A dynamic code so last-minute changes propagate without reprinting. Place it where people wait — outside rooms, at coffee stations, on table cards.
Badges: contact exchange. An encoded vCard lets people swap details with a scan instead of photographing a badge they cannot read later. Keep it trimmed — name, company, email, one number. A full vCard with a photo is too dense to scan from a lanyard at conversational distance.
Stands: WhatsApp with a pre-filled message. A code opening a chat containing "Hi, I visited stand 14" gives the exhibitor context automatically. Details in the WhatsApp guide.
Feedback while it is fresh. A code on the exit door or seat back, linking to a form of no more than three questions. Response rates collapse with every additional field, and entirely if the request arrives by email two days later.
Placement, ranked by what actually works
Table cards and seat backs. Seated, stationary, phone in hand. Best scan rates at any event.
Queue areas. Captive and bored.
Badges. Scanned in conversation, deliberately.
Room entrances. A pause point where people check they are in the right session.
Stand walls. Works if sized for where the crowd stops.
Corridor posters. Poor — people walk past.
Presentation slides. Very poor in a large room. Too small for row 20, and gone before people react.
If a code goes on a slide, leave it up for at least thirty seconds and size it for the back row.
After the event
The codes you printed still exist in bags and on badges for weeks. If they were dynamic, repoint them: slides, the recording, next year's registration. A code pointing at a dead event page is a wasted asset, and repointing costs nothing.
This is a strong argument for making agenda and stand codes dynamic even where static would have worked during the event.
Failures worth planning for
The venue network dies. Anything critical must work offline.
Screens too dim to scan. Train door staff to ask for brightness first.
Lanyards facing backwards. Print the badge code on both sides.
Codes below eye line. A code at knee height on a stand goes unnoticed.
One code for the whole event. You learn nothing.
A minimum set
For a mid-sized event, five codes cover most of the value: calendar on the invitation, registration on the poster, ticket on the confirmation, Wi-Fi at the entrance, feedback at the exit. Three of the five work without any network at all.
Start with the calendar code. Cheapest to produce, no infrastructure, most direct effect on whether people turn up.
Plan for the failure points
Give every operational code an owner and a fallback. If the Wi-Fi QR cannot join the network, staff need the network name and password. If a ticket scanner loses connectivity, there must be a manual check-in path. If a schedule changes, the dynamic destination should be updated before doors open and the printed sign should explain where to find the latest version.
Keep attendee data separate from convenience. A calendar link can be public; a ticket or check-in link should reveal only what the attendee needs. Avoid putting names, email addresses or reusable access tokens directly in a static QR pattern. The convenience of a scan is not a reason to make private event information easy to photograph and share.
