Twilio SMS allows you to:
When you buy a US domestic Twilio phone number, you can associate that phone number with an SMS Url. When someone sends a text message to that phone number, Twilio makes an HTTP request to your URL with the body of the message and the sender's phone number. You can then respond to the SMS by returning a reply message in HTTP response to Twilio.
You can also send SMS messages using Twilio's REST API. To send a message, just make an HTTP POST to Twilio with the body of the message and the phone number you want to send it to. SMS messages must be sent from Twilio SMS-enabled phone numbers due to the architecture of the global SMS network.
Using standard HTTP cookies, you can you share state across multiple messages allowing you to treat separate messages between any pair of phone numbers as a conversation, and store data about the conversation in the cookie for future reference.
You can also use the <Sms> verb inside your existing
Twilio voice calls to send a message during a phone conversation.
For specific details on what you can and can't accomplish using Twilio SMS please refer to the SMS FAQ
With that out of the way, let's go on to the next step