FreeSWITCH is both a WebRTC gateway and a WebRTC application server. It throws in the signaling plane too, with Verto. Let's introduce these concepts/functions:
FreeSWITCH is a WebRTC gateway because it's able to accept encrypted media from browsers, convert it, and exchange it with other communication networks that use different codecs and encryptions, for example, PSTN, mobile carriers, legacy systems, and others. FreeSWITCH can be a gateway between your SIP network and applications and billions of browsers on desktops, tablets, and smartphones.
FreeSWITCH is a WebRTC application server because it's able to directly provide native services to browsers, such as video conferences, IVRs, and call centers, without the use of any gateway or third-party. FreeSWITCH can directly provide services through Secure WebSocket (WSS), SRTP, and DTLS, the native WebRTC protocols.