Last updated:
09.03.2026
Double opt-in
Double opt-in (DOI) is a two-step consent process: After a user enters their contact details, they receive a confirmation message and must actively confirm their consent. Only then are they added to a marketing list.
In WhatsApp marketing, double opt-in is considered best practice for GDPR-compliant and high-quality list growth. hellomateo supports the double opt-in process seamlessly and in compliance with legal requirements.
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Double opt-in is the gold standard in permission marketing: Only those who have explicitly confirmed their consent may be contacted. This process protects companies from legal warnings, improves list quality, and ensures higher engagement among recipients who are genuinely interested.
How does double opt-in work?
The process takes place in two steps: In the first step, the user provides their contact details (e.g., mobile phone number for WhatsApp or email address). In the second step, they receive a confirmation message – via email, SMS, or WhatsApp – and must actively click on a link or send a message to confirm their consent.
Double opt-in and GDPR
The GDPR obliges companies to be able to prove consent for contact.
Double opt-in provides this proof automatically: Every confirmation is saved with a timestamp and IP address. This is crucial in case of a dispute. Double opt-in on WhatsApp with hellomateo: hellomateo offers an integrated double opt-in flow for WhatsApp: Interested parties can register via QR codes, landing pages, or click-to-WhatsApp links. Confirmation takes place directly in the WhatsApp chat – simple, user-friendly, and legally compliant. All consents are automatically documented in the CRM.
Advantages of Double Opt-in
- Legal certainty: Verifiable consent protects against legal warnings.
- Higher list quality: Only genuinely interested parties are included.
- Better engagement: Confirmers open and click more often.
- Fewer spam complaints: Clearly requested messages are not marked as spam.