Web Call Server is a WebRTC streaming media server designed for real-time low-latency streaming in browsers and native mobile apps. WCS is supplied with SDKs (Software Development Kit) for Web, Android and iOS platforms. Each SDK has a dozen of open source samples presenting server capabilities. Using these three SDKs with convenient API, developers can create such low-latency streaming applications as video chats, live broadcasting, video conferencing, screen sharing, live video transcoding, and low-latency audio and video delivery to desktop and mobile browsers on Android and iOS platforms. WCS supports SIP protocol and can operate as a WebRTC-SIP gateway or RTMP-SIP gateway. Using these features, developers can implement own browser-based or mobile applications such as web-phone, click-to-call, and various telephony cases and VoIP integrations for calling to external mobile or landline phones or for processing of VoIP calls on browsers and mobile apps. WCS supports RTSP protocol for work with IP cameras and CCTV systems. Using WCS, developers can create a cross-platform WebRTC mobile or browser-based application for low-latency video playback from IP cams and media servers with RTSP support. WCS uses a wide range of communication technologies and protocols such as WebRTC, RTMP, RTMFP, WebSocket, WebSocket streaming, HLS, RTSP, and SIP.