Two ways, and they are different solutions
Submission without sign-in
The user confirms the submission, but no session is created and no account is provisioned.
Needs a small server-side handler next to the form.
Sign-in with channel linking
The user signs in and you gain the channel along the way — if you have accounts and a member
area.
What the site gets
- proof of confirmation — who exactly (
sub) confirmed the submission and in which channel (channel_type); - a live channel to reply through: a message in the messaging app someone just confirmed in beats an address typed by hand;
- a bot filter that, unlike a CAPTCHA, gives the user nothing to solve: Telegram and some other channels report that the sender is a bot, Veriqa returns that flag in the claims, and such submissions can be cut off before a record is created.
This is a filter, not anti-fraud. It removes the stream of junk submissions; it does not replace
a fraud-prevention system.