You can explore Vonage Video API capabilities in the Playground demo web app, which allows you to publish a stream and subscribe to it using your own project API key, based on the OpenTok.js SDK with available SDK versions up to the second-to-last. To access the Playground, you need a Vonage Video API account, which can be signed up for with free credit to start building. The Playground requires no code writing, and upon logging in, users can publish a stream, subscribe to it, use signaling, archiving, broadcasting, and SIP capabilities, as well as demo features like screen-sharing and interactive publishing/subscribing.