QR Codes at events and trade shows

Events are where QR Codes promise the most and disappoint the most. They promise because everyone has a phone in hand and is willing to exchange contacts. They disappoint because the same crowd that creates the opportunity kills the data network — and most implementations depend on exactly that.

Problem number one: the network will fail

In a hall with thousands of people, the mobile network gets congested and event Wi-Fi is usually insufficient. Any QR Code that depends on opening a page has a real chance of failing precisely at peak time.

The practical consequence is that you should choose code types with the disconnected visitor in mind:

Works offline: contact (vCard), text, phone and SMS. The information lives inside the code.
Needs internet: link, WhatsApp and app download. They are excellent, but plan for the failure case.

For a booth, the most robust combination is a vCard — the visitor saves your contact on the spot, depending on nothing — plus a link code beside it for anyone with a connection who wants more.

At the booth

Size by traffic flow. A code on a backdrop banner, scanned from 3 metres, needs at least 30 cm. A code on the counter, scanned from 40 cm, is fine at 4 to 5 cm.
Eye level. A code at the foot of a banner forces people to crouch, and nobody crouches in a crowded aisle.
Watch the glass. Booths with acrylic or glass panels in front of the material reflect hall lighting and can make scanning impossible.
Say what they get. "Scan to receive the presentation" works far better than a bare code.

On badges

Badges with a contact QR Code turn networking into a two-second exchange, with no paper cards and no typing.

Use a lean vCard: name, company, job title, one email. Nothing beyond that.
Print at least 3 cm — badges are read close up, but vCards are dense.
Avoid the back: badges spin on lanyards constantly. If possible, print both sides.
Beware the glossy plastic sleeve, which reflects and interferes.

Check-in and tickets

Here the QR Code works in reverse: instead of the attendee scanning, they are scanned. Some specific precautions:

Do not depend on a phone screen. Low brightness, a cracked screen or a privacy filter make scanner reading harder. Offer printing as an alternative.
Tell people to raise their brightness while queuing. It resolves a good share of failures.
Have a fallback by name or ID. The queue cannot stop because of one dead battery.
Test the scanner under the real lighting of the check-in area before the event.

Track the origin of each code

If you use codes in different places — banner, brochure, staff badge, giveaway — make each slightly different so you know what worked:

On link codes, use distinct campaign parameters per piece.
On WhatsApp codes, change the ready message: "I came from the banner", "I picked up the brochure".
At the end of the event, you know which material actually produced conversations.

After the event

A detail that ruins campaigns: printed material outlives the event. Brochures taken home, badges kept, photos of the banner circulating on social media.

If the code points at an event-specific page, keep that page alive afterwards — with a redirect to something useful once the event ends. A code scanned three months later that opens "page not found" is a lost opportunity and a free bad impression.