Nextstrain is a comprehensive platform designed for real-time tracking of pathogen evolution, comprising a database of viral genomes, a bioinformatics pipeline for phylodynamics analysis, and an interactive visualization platform. The platform integrates sequence data with other types of information such as geographic data, serology, and host species, providing a single, accessible location for health professionals, epidemiologists, virologists, and the public. Nextstrain's core components include data curation, analysis, and visualization, with Python scripts maintaining a database of sequences and metadata from public repositories. The platform supports phylodynamic analysis, including subsampling, alignment, phylogenetic inference, and geographic reconstruction. The visualization interface allows simultaneous interrogation of phylogenetic and spatial relationships, providing a high-level overview of outbreak dynamics. Nextstrain also tracks and reconstructs mutations, displaying them as bar charts and highlighting adaptive changes. The platform emphasizes public data sharing, ensuring that derived data and metadata are available while maintaining control over raw sequences. This approach encourages collaboration and real-time dissemination of genomic epidemiological insights.Nextstrain is a comprehensive platform designed for real-time tracking of pathogen evolution, comprising a database of viral genomes, a bioinformatics pipeline for phylodynamics analysis, and an interactive visualization platform. The platform integrates sequence data with other types of information such as geographic data, serology, and host species, providing a single, accessible location for health professionals, epidemiologists, virologists, and the public. Nextstrain's core components include data curation, analysis, and visualization, with Python scripts maintaining a database of sequences and metadata from public repositories. The platform supports phylodynamic analysis, including subsampling, alignment, phylogenetic inference, and geographic reconstruction. The visualization interface allows simultaneous interrogation of phylogenetic and spatial relationships, providing a high-level overview of outbreak dynamics. Nextstrain also tracks and reconstructs mutations, displaying them as bar charts and highlighting adaptive changes. The platform emphasizes public data sharing, ensuring that derived data and metadata are available while maintaining control over raw sequences. This approach encourages collaboration and real-time dissemination of genomic epidemiological insights.