SMS or Viber/WhatsApp for Appointment Reminders?

For appointment reminders, SMS remains the most reliable channel: it reaches every phone, without internet, without an installed app, and without depending on notification settings. Viber and WhatsApp are excellent for conversations, but they assume the customer has the app, has a connection, and has not muted its notifications. Let's look at the comparison in detail.

The Critical Question: Will the Message Arrive?

An appointment reminder has one single purpose: to be read in time. It is not a promotional message where "if it gets lost, no harm done" — if it is not delivered, the cost is a possible no-show. So the first criterion is not price or message design, but certainty of delivery.

Where SMS Wins

• Reaches every phone — smartphone or not, with no app at all.
• Needs no internet — it is delivered even where data is off or weak.
• Read almost immediately — text messages are typically opened within minutes.
• Independent of settings — no muted chats, no "Requests" folders, no unknown-sender filters.
• Ideal for older or less tech-savvy customers too.

Where Viber and WhatsApp Win

To be fair, messaging apps have real advantages:

• Richer content — images, buttons, longer texts without the 160-character limit.
• Two-way conversation — the customer replies easily and the discussion continues.
• Viber is widespread in Greece and WhatsApp in Cyprus and internationally.

They are good choices for customer service and conversations. The problem appears when you entrust them with the critical, one-way reminder message.

The Weak Points of Apps for Reminders

• The app is required — any customer without it receives nothing.
• Internet is required — without a connection, the message waits.
• Notifications are often muted — a message marked "delivered" does not mean it was noticed in time.
• Messages from unknown business numbers can land in secondary folders or be treated with suspicion.
• Business sending accounts come with their own fees and terms (check each platform's current terms, as they change).

The Practical Answer: SMS + Free Push

The strategy Wiiz applies combines the best of both worlds: customers who have the Wiiz app receive the reminder as a free push notification, while everyone else receives an SMS from €0.06 per message. This way no customer is left without a reminder, and your cost stays low and predictable — with no monthly fee and no commission on appointments.

Frequently Asked Questions

Is SMS better than Viber for appointment reminders?

For the critical reminder message, yes: SMS reaches every phone without an app or internet, and is read almost immediately. Viber is useful for conversations, but it requires the app, a connection, and active notifications.

Can I send reminders only through WhatsApp?

You can, but you will only cover customers who have the app and active notifications. Business sending through WhatsApp also has its own fees and approval processes (check current terms). SMS has none of these preconditions.

How much does an SMS reminder cost with Wiiz?

From €0.06 per SMS for Greece and Cyprus, with no monthly fee and no commission. If the customer has the Wiiz app, the reminder goes out as a free push notification.

What works best for customers without a smartphone?

Only SMS. Text messages are delivered to basic phones too, something no Viber or WhatsApp can do. If your clientele includes older customers, SMS is the only way.