WhatsApp vs SMS: when to use which channel (and why 'both' is the real answer)

Both channels have massive reach, but they shine in different moments.

Use SMS when

• The message is time-critical: OTPs, fraud alerts, delivery windows.
• You need universal reach — every phone receives SMS, no app required.
• The content is short and one-way.

Use WhatsApp when

• You want a conversation: support, sales, booking.
• Rich content helps: images, buttons, product cards, documents.
• The customer already prefers it.

The real answer: let the platform choose

Instead of picking per campaign, define a fallback order and let WeZend route each message to the channel that customer engages with — WhatsApp first for a conversational nudge, SMS as an instant fallback. One API, one conversation thread, the best of both.

{
  "to": "+4512345678",
  "channel": "auto",
  "fallback": ["whatsapp", "sms"],
  "template": "delivery_update"
}