Exornata: A Web-based Tool for the Visualization and Editing of RNA Secondary Structures

• Exornata is modern web-based RNA structure editor with multi-format support. • It provides hierarchical constraint-based editing, formatting and labeling capabilities. • Exornata is integrated with R2DT to enable precise editing of template derived structures. • Exornata aims template-based standardization across RNA families. RNA secondary structures serve as a bridge between RNA sequences and often-unknown three-dimensional structures, offering insights into base pairing, structural motifs, and the overall organization of RNA molecules. To support efficient visualization and editing of these structures, we present Exornata, a modern, web-based editor designed to facilitate generation of detailed and standardized RNA secondary structure modeling. Exornata, is an expanded successor to the original XRNA software and is implemented using React and JavaScript/TypeScript technologies to ensure flexibility, interactivity, and high-quality rendering. Users can load, edit, and export RNA structures in multiple supported formats, ranging from conventional SVG to an advanced, in-house–developed JSON schema designed for interoperability with other resources such as R2DT, Traveler, and RiboVision2. The application supports multiple constraint-based editing modes (e.g. nucleotide, strand, helix, and domain) allowing precise and hierarchical manipulation of RNA elements. Exornata supports detailed, interactive visualization of canonical and non-canonical base pairs; it enables researchers to format and annotate structures, and to integrate them into broader bioinformatics pipelines. The tool is open-source, freely available at https://ldwlab.github.io/XRNA-React/ , and is accompanied by a user guide.