The case for WhatsApp usually starts with open rates. People read their WhatsApp messages and ignore a lot of their email, so the conclusion seems obvious: move everything to WhatsApp. It is the wrong argument, and following it tends to end with a blocked number and a lot of spend on messages nobody wanted.
The useful comparison is not which channel gets read. It is what each message costs, what you are allowed to send, and what your customers expect to receive where.
The cost is per message, not per list
Email has almost no marginal cost. Sending to a hundred thousand people costs little more than sending to ten thousand, which is why email can carry a weekly newsletter to an entire list without anyone doing the maths.
WhatsApp Business messages that you start, using approved templates, are charged by Meta per delivered message, with rates that vary by country and by category: marketing, utility or authentication. Replies inside the customer service window, the 24 hours after a customer last messaged you, are not charged. So the economics are the reverse of email: every outbound marketing message has a price, and conversation the customer starts is cheap.
That changes what the channel is good for. A broadcast to everyone is expensive and rarely worth it. A message to the few hundred people who left a high-value cart this afternoon often is.
Consent is stricter, and it shows
To message someone on WhatsApp you need their explicit opt-in to hear from you there. A newsletter signup does not cover it. That is the law in most markets and Meta's policy everywhere.
Consent quality also has consequences you can see. People can block or report a business in one tap, and a high rate of either lowers your number's quality rating, which can restrict how many people you can message. Email has spam complaints too, but a WhatsApp message lands in the same list as messages from family. The tolerance for anything that feels like noise is far lower.
Where WhatsApp wins
- Time-sensitive moments. Abandoned carts, back-in-stock alerts for an item someone asked about, delivery updates, appointment reminders. The value is that it is seen within minutes.
- Considered purchases that need a conversation. Furniture, electronics, treatments, anything where a question answered quickly is the difference between a sale and a bounce. The reply comes back in the same thread, and it is free inside the service window.
- Markets where WhatsApp is the default. In Israel, much of Latin America, southern Europe, India and the Gulf, customers expect to reach a business on WhatsApp. Email can feel formal or slow there.
- Customers who never open email. If someone has consented to WhatsApp and ignored the last ten emails, a single well-timed message may reach them where nothing else does.
Where email still wins
- Long-form and browsable content. Newsletters, lookbooks, guides, anything with several products or more than a few lines of text.
- Frequent, low-margin promotions. When a single message has to pay for itself on a small basket, per-message pricing rarely works.
- The whole list. Everyone who has given you an email address and not opted into WhatsApp. That is usually most of them.
- Records. Receipts, invoices and terms that people want to search for later.
Use them in the same journey, not side by side
The question is rarely “WhatsApp or email”. It is which one goes first, and what triggers the second. A pattern that works for cart recovery:
- Email an hour after the cart is abandoned.
- If the email is not opened and the cart is above a value threshold, and the customer has opted into WhatsApp, send one WhatsApp message the next day.
- If they reply, answer in the thread; that conversation is inside the service window.
- Stop everything the moment they buy.
Two rules make this work. First, one frequency cap across all channels: a customer should not get an email, an SMS and a WhatsApp about the same cart. Second, one consent record: the channel a customer agreed to is checked before every send, not only when the journey was built.
In FORTVISION: email, SMS and WhatsApp are steps in the same journey, read from one contact record with per-channel consent, and replies land in the shared inbox next to the customer's orders and previous messages.
WhatsApp is not a better email. It is a more expensive, more personal channel that pays off when the moment is urgent or the conversation matters. Treat it that way and the open rates take care of themselves.