Twilio

Twilio SMS pricing is per-message and varies by country. US outbound SMS costs $0.0079 per message. Inbound SMS is $0.0075. International pricing varies — EU messages cost $0.04–$0.10 per message. The $2,500 startup credit covers approximately 316,000 US outbound messages or proportionally fewer international messages.

Yes — Twilio Verify is the dedicated 2FA API. It handles code generation, delivery via SMS/voice/email/WhatsApp, code verification, rate limiting, and fraud prevention. At $0.05 per verification, it is cheaper and more secure than building custom 2FA. The Verify API is the recommended approach for user registration and login verification.

Twilio supports SMS in 180+ countries and voice in 100+ countries. Phone number provisioning is available in 50+ countries for local numbers and globally for toll-free numbers. Check Twilio's coverage page for specific country availability. Most startups serving global users can use Twilio for all their communications needs.

AWS SNS provides basic SMS sending at lower per-message cost ($0.00645 in the US). Twilio provides a complete communications platform — SMS, voice, video, WhatsApp, verification, conversation management — with better developer experience, phone number management, and delivery analytics. For basic notifications, SNS is cheaper. For communications-as-a-feature, Twilio is more capable.

Yes. Twilio supports WhatsApp Business API messaging through the same API used for SMS. Send text, images, documents, and interactive messages to WhatsApp users. Requires WhatsApp Business account approval and message template approval for outbound messages. The WhatsApp channel uses the same Twilio credits as other services.

Yes. Twilio Programmable Voice enables making and receiving phone calls, building IVR (interactive voice response) systems with keypad input, call recording, call transcription, conference calling, and voicemail. Call flows are defined using TwiML (Twilio Markup Language) — an XML-based language that's straightforward to learn.