Double opt-in is a signup process where new subscribers confirm their address by clicking a link in a confirmation email before being added to your list.
In depth
Double opt-in produces a cleaner, more engaged list by filtering out typos, fake addresses and bots, which lowers bounces and complaints and improves deliverability. The trade-off is slightly lower raw signup numbers because some people never confirm. The alternative, single opt-in, adds subscribers immediately without confirmation.
Example
After entering their email, a user receives a confirmation email and must click a link to join the list.
Related terms
See our full email marketing glossary or the complete email marketing guide.