The ExPASy (Expert Protein Analysis System) World Wide Web server, provided by the Swiss Institute of Bioinformatics (SIB), offers a comprehensive suite of databases and analytical tools dedicated to proteins and proteomics. Key databases include SWISS-PROT, TrEMBL, SWISS-2DPAGE, PROSITE, ENZYME, and the SWISS-MODEL repository. These resources are interconnected, with a focus on integrating database entries with related SIB-developed resources. ExPASy provides tools for similarity searches, pattern and profile searches, post-translational modification prediction, topology prediction, and sequence alignment. The server has been operational since 1993 and currently operates with seven mirror sites worldwide. Academic users can access all databases for free, while commercial users are charged an annual subscription fee to support database updates and enhancements. ExPASy also offers a variety of software tools for protein sequence analysis and proteomics data processing, including automated sequence alerting systems and biochemical pathway visualization. The server aims to provide top-quality information services in proteomics and encourages users to link to ExPASy for easy access to its resources.The ExPASy (Expert Protein Analysis System) World Wide Web server, provided by the Swiss Institute of Bioinformatics (SIB), offers a comprehensive suite of databases and analytical tools dedicated to proteins and proteomics. Key databases include SWISS-PROT, TrEMBL, SWISS-2DPAGE, PROSITE, ENZYME, and the SWISS-MODEL repository. These resources are interconnected, with a focus on integrating database entries with related SIB-developed resources. ExPASy provides tools for similarity searches, pattern and profile searches, post-translational modification prediction, topology prediction, and sequence alignment. The server has been operational since 1993 and currently operates with seven mirror sites worldwide. Academic users can access all databases for free, while commercial users are charged an annual subscription fee to support database updates and enhancements. ExPASy also offers a variety of software tools for protein sequence analysis and proteomics data processing, including automated sequence alerting systems and biochemical pathway visualization. The server aims to provide top-quality information services in proteomics and encourages users to link to ExPASy for easy access to its resources.