Opt-in

Opt-in is the customer's explicit consent to receive messages. It is required by LGPD (Brazil), GDPR (Europe) and WhatsApp's own policy. Without opt-in, sending mass messages is illegal spam — subject to fines and number banning.

How to get legit opt-in

• Explicit checkbox in form: "I agree to receive communications via WhatsApp".
• Active Customer Response: he sent you a message asking for information.
• Order confirmation: customer provided telephone number to track delivery.
• Loyalty program: accepted terms that mention communication via WhatsApp.

What is NOT opt-in

• Purchased list — even if you have a phone, you do not have consent.
• Phone taken from business card or social network.
• Telephone number of an old customer who never authorized it.

Passive vs Active Opt-in

Passive opt-in (checkbox pre-marked, policy assumed) is legally weak — can be questioned. Active opt-in (customer explicitly clicks/checks in) is the only defensible way. In commercial communication via WhatsApp, always use active opt-in.

Documentation

Keep record of the opt-in: date, IP, form used, exact text of the consent. The LGPD requires that you can demonstrate consent (article 8). In the event of a complaint, this record is the only defense.

See also: opt-out and sending bulk messages LGPD-compliant.