Double opt-in adds a confirmation step to signing up. In Mailchimp’s email process, a person submits a form and then clicks a confirmation link in an email before becoming a subscribed contact. This describes the sign-up mechanism, rather than a complete assessment of marketing permissions. Source: Mailchimp: Double opt-in

Explain the next step clearly

Use the sign-up confirmation screen to tell the person to check their inbox and complete the request. Make the confirmation email recognisable and test its link. This helps someone understand why submitting the form is only the first part of the process.

Check every route into the list

Ask the email provider to confirm how website forms, integrations and imported records handle subscription status. Keep the permission wording and confirmation record together. This makes the process easier to review when someone asks how an address joined a mailing list.

Written and updated by Travelgenix. Sources checked on 19 October 2026. Practical advice and examples are Travelgenix editorial guidance.