Hardwell's style can be Classified in different sub genres of the electro-house music. He describes his starting style as influenced by the hip-hop underground scene. Between 2005 and 2006, he developed his style more commercially and over time his productions were increasingly based on a mix of Tech House and Dirty Dutch. Around the year 2008 his songs became slower and more commercial. In parallel, he experimented with elements from other genres. During that time, he came up already with build-ups, which were very similar to the big-room genre that had emerged years later. With the release of the Single "Feel So High" in 2009, he published a tech-house song that corresponded to the classical progressive house, which was dying out, especially at the time.