JPred4 is the latest version of the popular protein secondary structure prediction server, which uses the JNet algorithm to provide highly accurate predictions. In addition to secondary structure, JPred4 also predicts solvent accessibility and coiled-coil regions. The server has been re-implemented using the Bootstrap framework and JavaScript to enhance its design, usability, and mobile accessibility. JPred4 offers higher accuracy, with a blind three-state secondary structure prediction accuracy of 82.0% and solvent accessibility prediction accuracy of 90% for residues with ~5% accessibility. The server supports single protein sequences, multiple sequence alignments, and batch submissions, and provides results through a web interface or email summaries. The updated version includes enhanced visualization options, step-by-step tutorials, and improved alignment viewing capabilities. The median time for a prediction to return results is 5 minutes, and the server can handle jobs up to 3 hours in duration.JPred4 is the latest version of the popular protein secondary structure prediction server, which uses the JNet algorithm to provide highly accurate predictions. In addition to secondary structure, JPred4 also predicts solvent accessibility and coiled-coil regions. The server has been re-implemented using the Bootstrap framework and JavaScript to enhance its design, usability, and mobile accessibility. JPred4 offers higher accuracy, with a blind three-state secondary structure prediction accuracy of 82.0% and solvent accessibility prediction accuracy of 90% for residues with ~5% accessibility. The server supports single protein sequences, multiple sequence alignments, and batch submissions, and provides results through a web interface or email summaries. The updated version includes enhanced visualization options, step-by-step tutorials, and improved alignment viewing capabilities. The median time for a prediction to return results is 5 minutes, and the server can handle jobs up to 3 hours in duration.