Realtime Prices, Sentiment, Tweets, Scuttles, News and discussions on Twilio Inc. Twilio (pronounced TWILL-e-o) is a cloud communications (PaaS) company based in San Francisco, California. Twilio allows software developers to programmatically make and receive phone calls and send and receive text messages using its web service APIs. Twilio's services are accessed over HTTP and are billed based on usage. As of February 2015, more than 560,000 developers use the service.