What counts as opt-in
- A checkbox on your site or checkout that names the channel: “Send me offers on WhatsApp” or “SMS alerts about my order”.
- The customer messages you first. That covers the 24-hour window. It does not give you a permanent right to send weekly promotions.
- A keyword they send because a poster, receipt, or staff member asked them to, with the business name visible.
A phone number collected for a delivery is not opt-in for a marketing blast. Transactional updates about that order are a different job from a sale.
What to store
Keep the source, the date, and the channel. “Website checkout, 12 Oct 2026, WhatsApp marketing” is enough for a dispute. A spreadsheet of numbers with no source is not. When someone says stop, record that too and suppress them on the next send.
Marketing templates go only to people who opted in, and the template should say how to stop. Utility templates are for the thing they already asked for: a booking, a shipment, a password. Mixing a discount into a utility template is how templates get rejected and how quality drops.
SMS
Promotional SMS needs consent. OTP and alerts about an action the person just took are transactional, and they should use the sender ID registered for that traffic. An alphanumeric sender often cannot receive a reply, so “reply STOP” does not work on it. Put the opt-out on a numeric sender that accepts replies, or take them to a page. Sender ID rules by country are in SMS sender ID in MENA.
Lists that are not opt-in
- Numbers bought from a broker.
- Contacts scraped from groups or old phone books with no ask.
- A partner’s customer list, unless those people were told your brand would message them and they agreed.
FAQ
Do I need opt-in to message customers on WhatsApp?
Yes for business-initiated messages, and especially for marketing. A customer who messages you first opens a 24-hour window. That is not ongoing permission for promotions.
Is a checkout phone number enough for SMS marketing?
No. Use it for updates about that order. A promotion needs a separate consent that names SMS or WhatsApp.
Can customers reply STOP to an alphanumeric sender ID?
Usually no, because those sender names are one-way. Use a numeric sender that accepts replies, or a link, and still suppress the number in your list.
Ready to send? Start free trial · Talk to sales
