PredictProtein (PP) is an internet service for sequence analysis and prediction of protein structure and function. Users submit protein sequences or alignments, and the server returns a comprehensive set of results, including multiple sequence alignment, PROSITE motifs, low-complexity regions, domain assignments, nuclear localization signals, regions lacking regular structure, secondary structure predictions, solvent accessibility, globular regions, transmembrane helices, coiled-coil regions, structural switch regions, and disulfide bonds. Fold recognition by prediction-based threading is also available upon request. PP has been operational since 1992, initially at the European Molecular Biology Laboratory (EMBL) and later moved to Columbia University. It remains one of the most widely used public servers for structure prediction, handling over one million requests from 95 countries. The server aims to provide a single, comprehensive output by concatenating results from various high-quality prediction methods, making it accessible through email and web interfaces. The output is designed to be user-friendly, with default settings that focus on high-confidence predictions. Advanced options allow users to customize the output and request specific methods. PP's success is attributed to its comprehensive approach, user-friendly interface, and continuous updates to improve accuracy and performance.PredictProtein (PP) is an internet service for sequence analysis and prediction of protein structure and function. Users submit protein sequences or alignments, and the server returns a comprehensive set of results, including multiple sequence alignment, PROSITE motifs, low-complexity regions, domain assignments, nuclear localization signals, regions lacking regular structure, secondary structure predictions, solvent accessibility, globular regions, transmembrane helices, coiled-coil regions, structural switch regions, and disulfide bonds. Fold recognition by prediction-based threading is also available upon request. PP has been operational since 1992, initially at the European Molecular Biology Laboratory (EMBL) and later moved to Columbia University. It remains one of the most widely used public servers for structure prediction, handling over one million requests from 95 countries. The server aims to provide a single, comprehensive output by concatenating results from various high-quality prediction methods, making it accessible through email and web interfaces. The output is designed to be user-friendly, with default settings that focus on high-confidence predictions. Advanced options allow users to customize the output and request specific methods. PP's success is attributed to its comprehensive approach, user-friendly interface, and continuous updates to improve accuracy and performance.