The Twilio API is extremely capable, and you can do pretty much anything you can imagine involving a phone with it. However, the documentation for their official API wrappers is very minimal. I've had to assemble most of my code through a combination of hacking together sample code from several different sources and trial and error.I was also a little disappointed in the TwilioJS library, which does a nice job of powering WebRTC connections, but lacks basic metadata about those calls, such as the Call SID. This means you have to send a separate query to the API to comb through all calls until you find the one that your session is connected to. Just seems like a lot of unnecessary overhead.Overall, they offer a good service, and I'll likely continue to use them. I'd be ranting and raving though if they could improve those two areas.
