Overview SMS is one channel in Twilio's Messaging platform. All channels — SMS, WhatsApp, RCS, Facebook Messenger — share the same API. See for the full channel comparison and onboarding sequence. | When to use SMS | When to consider alternatives | |----------------|------------------------------| | Reach any phone number globally | Need rich media outside US/CA/AU → WhatsApp | | No app install required | Opted-in audience prefers chat apps → WhatsApp | | Time-sensitive alerts (OTP, outage) | Marketing campaigns → | | Regulatory/compliance requires SMS | Cost-sensitive high-volume → WhatsApp…