Expasy is an online bioinformatics resource operated by the SIB Swiss Institute of Bioinformatics. It is an extensible and integrative portal which provides access to over 160 databases and software tools and supports a range of life science and clinical research areas, from genomics, proteomics and structural biology, to evolution and phylogeny, systems biology and medical chemistry. The individual resources (databases, web-based and downloadable software tools) are hosted in a decentralized way by different groups of the SIB Swiss Institute of Bioinformatics and partner institutions.