In 2015 I wrote a whole Contact Management app for a business that let their entire sales team of like 50 reps pick up phone calls from the browser or from their desk phone using Twilios SIP trunk service. It was pretty cool, it routed the calls to both our internal Asterisk server, and worked flawlessly with Twilios WebRTC libraries in the web app. It was really cool and surprisingly easy, also all of the call recordings instantly became available in the web app and they could initiate calls from their call calendar in the app.