Protein kinases are involved in many cellular signaling pathways and comprise one of the largest families of homologous proteins. They play an extensive role in signal transduction and regulation of the complex cellular processes necessary to maintain life. Overexpression and/or dysregulation of protein kinases lead to a variety of diseases, thus providing numerous targets for drug development. Currently, approximately 24% of all research spending on drug discovery and development is focused on kinases. In view of the huge demand for small molecules that target this class of proteins, many technologies and platforms have been developed for the discovery of kinase inhibitors, including biochemical-based functional assays and compound-binding competition assays.