How to choose

How to pick a sender

1. Where do the recipients live? US or Canada: numbers (10DLC, toll-free, short code), RCS or WhatsApp. Elsewhere, start from the country's alpha pattern, then ask whether people read SMS at all. In Latin America WhatsApp is the default business channel; I'm sure of that, though I haven't seen solid usage figures.
2. Do they need replies? Then alpha is out.
3. What's the peak, not the average? Providers say a low-scoring 10DLC campaign gets 240 texts a minute at AT&T. Flash sales and OTP spikes need a high vet score or a short code.
4. Marketing, transactional or one-time passcode? The category sets the consent bar, the campaign type, quiet hours, the WhatsApp price and, in India, the header suffix. Right now WhatsApp doesn't deliver marketing templates to US numbers at all.
5. How soon, and does the brand have to show? WhatsApp can be live in minutes, 10DLC in days, toll-free in days to weeks, a US short code in weeks to months. Branded options: alpha (outside North America), RCS, WhatsApp and, for calls, branded calling.

My defaults: for a US customer, 10DLC for conversational and transactional traffic, toll-free for one national number at modest volume, and a short code only when the volume justifies a prepaid lease and the wait. Abroad, a registered alpha for one-way alerts and OTPs, WhatsApp where people live in it, and local numbers only when replies matter and the country allows business texting on them.