A racket dampener swing sensor apparatus to obtain measurements of parameters relative to the player's performance while reducing vibration includes a dampener body having a body front side, a body back side, and a body perimeter. The body perimeter has a string channel to selectively engage a plurality of strings of a tennis racket. The dampener body absorbs vibration from the plurality of strings. An accelerometer and a microcontroller with memory are coupled within the dampener body to measure hit velocity for each shot type (forehand, backhand, serve, topspin, slice, or flat). A vibration sensor is provided to detect when a ball is struck. A transceiver is coupled within the dampener body to wirelessly communicate with an app on a smartphone or computer. A battery is coupled within the dampener body and a charge port is in operational communication with the battery.