WhatsApp has 2B+ users globally and dominates in LATAM, India, Southern Europe, and parts of Africa. Open rates exceed 95%. Far above any email channel.
Templated messages (HSMs) require Meta approval but can be sent to opted-in customers at any time. Conversational replies are free within 24 hours of the user's last message.
Callsy is rolling out WhatsApp Business API support, booking confirmations, payment reminders, and cart-recovery follow-ups will pair with voice, SMS, and email once it ships. Currently supported channels: voice, SMS, email.