TreeTime

TreeTime is an open-source tool for organizing notes, tasks, and structured data in hierarchical trees. It runs locally with no account required, and stores everything in plain text files — keeping your data private and portable. What sets TreeTime apart is that each item can exist in multiple trees simultaneously, so you can view the same information from different perspectives without duplicating it. Calculations like sums, ratios, and differences update automatically across branches, making it well-suited for project tracking, research, or any workflow where data has natural nested relationships. Browsing is interactive: TreeTime optionally serves your trees to a local read-only web interface using SVG graphics and clickable links, letting you explore complex structures visually without changing the underlying data. Export to PNG, SVG, HTML, CSV, and plain text is also supported.