VisiData is a terminal-based interactive spreadsheet application for exploring, cleaning, restructuring, and analyzing tabular data. It provides a real-time curses interface for loading data from diverse sources (CSV, JSON, Excel, SQL databases, APIs, etc.), applying transformations via hundreds of keyboard-driven commands (sort, filter, pivot, melt, unfurl, etc.), and saving results. The architecture centers around a Sheet/Column abstraction with a plugin system for loaders, features, and specialized applications (vgit for Git, vdsql for SQL). Key strengths include its extensible command system, dynamic type inference, and reversible operations via undo/redo. While the core is cohesive, the extensive optional dependencies and experimental features introduce some maintenance complexity.