The VTI Companion App is a third-party application for VRChat Twitch Integration (For Worlds!). It acts as a go-between and allows a VRChat World with the VTI World Kit installed to connect with Twitch and allow a streamer's chat to trigger special effects. As VRChat itself has no way to connect to web services or APIs like REST on its own, the Companion uses native VRChat functionality to bridge the gap and allow VTI to function. For more detailed information on how the Companion achieves this, please see VTI Function Overview.
Download the Companion App: https://stevegreendesign.com/project/vti/