Can attendees exchange details by tapping badges?
Not badge to badge, ever. Both are passive objects with no power of their own, so neither can energise or read the other. What works is each person reading the other's badge with their phone, which needs a destination that requires no application.
Why badge to badge cannot work
A tag has no battery. It is powered by the field a reader produces, and it produces no field of its own.
Two badges touched together are two objects waiting to be powered, with nothing to power them. Nothing happens, and nothing can.
This is worth stating plainly because the expectation is common and the demonstration people imagine is impossible rather than merely unsupported.
And why phone to phone does not either
Phones can produce a field, so two phones is a more reasonable expectation. The mode that allowed them to exchange data by touching has been withdrawn from the platforms.
What remains is one phone acting as a reader and the other as a card, which is how payment works and is not a general purpose exchange between two people.
So an attendee to attendee exchange by touching phones is not something to plan around either.
What does work
Each person reads the other's badge with their own phone. The badge holds an address, the phone opens it, and the page offers the other person's details.
That is two taps rather than one gesture, and it works today on the phones people are carrying.
The exchange is one directional per tap, which is honest: each person chooses to read the other, and consent is explicit on both sides.
An exhibitor with a supplied reader is the same pattern with better equipment, which is why lead capture works reliably while attendee exchange feels awkward.
Designing the exchange
Put a web address on the badge, not a contact record, so the destination can require no application and can be changed.
Decide what the page shows before consent. A badge that reveals someone's mobile number to anyone who taps it in a crowded hall is a privacy failure, not a feature.
A better pattern is a page that identifies the person minimally and offers to connect, with the details exchanged once both have agreed in the event system.
And tell attendees how it works, at registration and on the badge. An exchange nobody knows about does not happen, and an exchange people misunderstand produces complaints.
Frequently asked questions
Why do two badges do nothing when touched?
Both are passive and neither produces a field, so there is nothing to power the other. It is impossible rather than unsupported.
Can we tap two phones together instead?
The mode that allowed that has been withdrawn from the platforms. What remains is one phone reading and the other emulating a card.
Is a contact record on the badge better?
No. It freezes the details, exposes them to anyone who taps the badge, and cannot be changed. An address is safer and more flexible.
Should the page show a phone number?
Not before both people have agreed. A badge worn in a crowded hall can be read by anyone standing close.