Double Opt-In

Double opt-in (also called confirmed opt-in) is a two-step subscription process: a person submits their address, then must click a link in a confirmation email to prove they own the address and want the mail.

Why it matters

It keeps typos, bots and addresses entered by other people off a list, which protects sender reputation and reduces the chance of hitting spam traps. It also provides a record of consent, which some regions' privacy rules, such as the GDPR, make valuable; legal requirements vary by country, so check the rules that apply to you. The cost is that some genuine people never click, so the list grows more slowly. Single opt-in adds the address immediately without confirmation.

Example

Flow:

1. A visitor enters jane@example.com in a form.
2. The system sends: "Please confirm your subscription" with a unique link such as https://example.com/confirm?t=9f3a....
3. Only when Jane clicks is she marked as confirmed and moved onto the list.

Store the timestamp, IP address and the form used at confirmation as evidence.

Common mistakes

• Sending the confirmation email through a poorly authenticated domain, so it lands in spam.
• Making the link expire in minutes.
• Adding unconfirmed addresses to the list anyway.

Related

• List Hygiene
• Email Marketing
• Spam Trap
• GDPR
• Tool: Email deliverability test

This page is general information written by our editorial team and updated when documentation changes. Servers and providers differ, so test changes safely first. See our editorial policy and disclaimer.