The analytical profile index, or API, is a classification system for bacteria based on biochemical tests. The system was developed to accelerate the speed of identifying clinically relevant bacteria. It can only be used to identify known species from an index. The data obtained are phenotypic traits. DNA sequence-based methods, including multi-locus sequence typing and even whole-genome sequencing, are increasingly used in the identification of bacterial species and strains. These newer methods can be used to complement or even replace the use of API testing in clinical settings.