Double opt-in
Confirming a subscription by email before you send anything else, and why it is worth the signups it costs
Double opt-in means a person who submits your signup form is not subscribed yet. They are sent one message with a confirmation link, and only a click on that link subscribes them. Single opt-in subscribes them on submission.
Double opt-in costs you signups. Somewhere between ten and thirty per cent of people never click, and that is the real objection to it.
Why it is usually still right
- It proves the address exists and belongs to the person who typed it, which removes typos, throwaway addresses and other people's addresses in one step.
- It is the strongest available answer to "I never signed up for this", which is the most common reason for a complaint — and complaints cost far more than the signups you lost.
- It keeps spam traps off your list, which purchased and scraped lists cannot do at all.
- In several jurisdictions it is the easiest way to evidence consent if anyone asks.
The signups it costs were mostly never going to engage. The ones it keeps are the ones mailbox providers score you on.
In Sendly
Sendly does not force a subscription flow on you: subscription happens through the API or an import, so the confirmation step is yours to build. The pieces are all here — a transactional send for the confirmation message, a contact custom field or list membership to record the state, and a workflow if you want to chase people who did not confirm.
Whatever you choose, import your previous provider's suppression list before your first send.