TreeSheets

TreeSheets provides a single‑window environment where data can be entered in cells that are organized hierarchically, allowing rows to contain nested sub‑rows. This structure lets users treat the document as a spreadsheet, an outline, a mind map, or a lightweight database, depending on the task. Cells can hold plain text, dates, or simple formulas, and the hierarchy can be expanded or collapsed to focus on relevant sections.

The application targets anyone who needs to manage structured information without switching between separate tools—students, project planners, developers, and anyone maintaining to‑do lists, calendars, or brainstorming notes. Because the interface resembles a familiar spreadsheet while supporting multiple dimensions of organization, it reduces the learning curve for users accustomed to traditional spreadsheets or outliners.

TreeSheets is distributed as a free, open‑source program for macOS, Windows, and Linux. It is deliberately lightweight, using only a few megabytes of memory even with many documents open, and runs continuously from the system tray. Source code, releases, and community discussion are hosted on GitHub, with additional support channels on Discord and a Google group.