Its absolutely possible to use external JS libraries with Framer. I use them all the time to speed up my prototyping. Heres an example of a simple prototype using this library (http://leocs.me/jquery-drawsvg/) for animating SVG's - https://framer.cloud/vjMuS
I use GSAP for SVG animation. Here's an example of using GreenSock in Framer.https://dribbble.com/shots/3569278-Framer-GSAP-Monitoring-Icon-Animation
Sergey Nikishkin Thats really cool!