Reflex-in is a sound installation that uses brain-wave streams to create music composition within the Web environment in real time. The work incorporates various state-of-the-art Web technologies, including Web Audio, WebSocket, WebAssembly, and WebGL. The music generated from the algorithm - mapping brain wave signal to musical events - aims to produce a form of furniture music that is relaxing and meditative, possibly therapeutic. This effect can be further enhanced through binaural beats or other forms of auditory stimulation, also known as ``digital drugs,'' which can be enabled through the user interface. The system represents a potential avenue for the development of closed-loop brain-computer interfaces by using the listener's own brain waves as the source of musical stimuli, which can be used for therapeutic or medical purposes.