Sydney Sierota is an American singer and songwriter, best known as the lead vocalist of the pop band Echosmith. Born on April 21, 1999, in Los Angeles, California, she gained fame with the band's hit single "Cool Kids," which was released in 2013. The song received significant radio play and helped establish Echosmith in the music industry. In addition to her work with Echosmith, Sydney has collaborated with various artists and contributed to the band's albums, showcasing her talent for writing catchy melodies and relatable lyrics. She continues to be an influential figure in the pop music scene.