Double opt-in

One confirmation click turns a typed address into provable consent.

Double opt-in is a signup flow in which a new subscriber must click a confirmation link emailed to them before they join a list. The click proves that the mailbox's actual owner asked for the mail, rather than a typo, a bot, or someone else entering the address.

Why it matters

The click is evidence, not friction. Under GDPR the sender carries the burden of proving consent, and a stored confirmation record, with token, timestamp, and source, is the cleanest proof there is; German case law effectively expects it. The list-quality effect is just as concrete. Unconfirmed signups are where typos, bots, and forged submissions live, and those addresses become the bounces and spam complaints that erode sender reputation months later.

In practice

The flow: a form submission creates a pending subscriber and sends exactly one confirmation email containing a unique token link. On click, the subscriber becomes active and the consent event is stored. Without a click, the pending record expires and the address never receives another message. Some fraction of real signups never confirm, and that is the honest cost, but the loss is concentrated in the addresses you were better off without.

How Email Fast handles it

Email Fast ships hosted signup forms with double opt-in through our own delivery path, so every subscriber carries verifiable proof of consent. The confirmation emails ride the transactional lane, so a confirmation email is never held back by marketing suppression, and the stored consent record is attached to the subscriber where an audit can find it.