The CGView Server is a web-based tool designed for visualizing circular genomes, including bacterial, plasmid, chloroplast, and mitochondrial genomes. It generates graphical maps that display sequence features, base composition plots, analysis results, and sequence similarity plots. Users can submit sequences in various formats (raw, FASTA, GenBank, EMBL) and additional feature information in GFF files. The server uses BLAST to compare the primary sequence with up to three comparison genomes or sequence sets, converting the results into a graphical map. The map can be customized to show different types of features and can be used to identify conserved segments, instances of horizontal gene transfer, and differences in gene copy number. The CGView Server also allows for the visualization of newly obtained sequence reads in known genomes. The tool is accessible at http://stothard.afns.ualberta.ca/cgview_server/. Despite returning static images, the CGView Server offers a comprehensive and customizable approach to visualizing circular genomes, making it a valuable resource for comparative genomics.The CGView Server is a web-based tool designed for visualizing circular genomes, including bacterial, plasmid, chloroplast, and mitochondrial genomes. It generates graphical maps that display sequence features, base composition plots, analysis results, and sequence similarity plots. Users can submit sequences in various formats (raw, FASTA, GenBank, EMBL) and additional feature information in GFF files. The server uses BLAST to compare the primary sequence with up to three comparison genomes or sequence sets, converting the results into a graphical map. The map can be customized to show different types of features and can be used to identify conserved segments, instances of horizontal gene transfer, and differences in gene copy number. The CGView Server also allows for the visualization of newly obtained sequence reads in known genomes. The tool is accessible at http://stothard.afns.ualberta.ca/cgview_server/. Despite returning static images, the CGView Server offers a comprehensive and customizable approach to visualizing circular genomes, making it a valuable resource for comparative genomics.