Whatsapp Business. $0.03-0.06 per conversation / authentication (multiple messages within 24hs) depending if it's transactional or marketing.
SMS providers are unreliable and expensive, it's eating their business.
SMS providers are unreliable and expensive, it's eating their business.
Is it actually though? At least in the UK I still get every business message (delivery notifications, booking confirmations etc.) via SMS. I haven't received a single one via WhatsApp. And WhatsApp has 100% penetration here so that isn't a barrier.