Textual

Textual is a rapid application development (RAD) framework for Python that enables developers to build sophisticated, interactive user interfaces that run in the terminal or in a web browser from a single codebase. Created by Will McGugan (founder of Textualize.io and creator of the Rich library), Textual has grown to over 36,400 GitHub stars and 1,200 forks, with the current version being v8.2.7. The framework implements a complete widget toolkit inspired by modern web development paradigms, with a CSS-like styling system, a reactive programming model, a flexible layout engine, and a comprehensive event system. Textual provides over 30 built-in widgets including Button, Checkbox, DataTable (sortable, interactive tables), DirectoryTree, Input, Label, Link, ListView, MarkdownViewer, ProgressBar, Select, Sparkline, TabbedContent, Tabs, TextArea, Tree, Toast, Footer, Header, Rule, Switch, Collapsible, OptionList, and LoadingIndicator. The framework uses a DOM-like architecture where widgets are composed into a tree hierarchy, queryable via CSS selectors and DOM queries. Styling is controlled through a Textual CSS system supporting properties for layout (align, dock, grid, layers, layout, offset, position), dimensions (width, height, min-width, max-width, padding, margin), appearance (color, background, border, opacity, tint, hatch, text-align, text-style, scrollbar), and behavior (visibility, display, overflow, box-sizing). Textual apps can run natively in the terminal with full mouse support, over SSH for remote access, or be served as web applications using textual-serve. The framework is built on top of the Rich library for rich text rendering and includes a DevTools dashboard for debugging, command palette, animation system, worker threads for async operations, screen management for multi-screen apps, and comprehensive testing utilities.