Pre-release. The API may still change before 1.0. Full documentation is at bootstack.org.

From idea to a shipped desktop app — fast.

bootstack gives engineers, data scientists, and hobbyists everything to build a polished desktop interface and package it into a standalone executable — declarative, reactive, and batteries-included, all in pure Python.

Why bootstack?

Most Python desktop frameworks make you fight the framework. bootstack gets out of the way.

• 30% less code — the declarative, context-manager layout eliminates geometry calls, explicit parenting, and most of the wiring boilerplate
• Reads like Python — nested with blocks mirror your UI structure; the code hierarchy is the layout
• Modern layout system — HStack, VStack, and Grid containers handle spacing, alignment, and fill automatically; CSS conventions (gap, padding, margin, fill, anchor) without writing CSS
• 60+ widgets out of the box — primitives through full composites: tables, trees, calendars, date pickers, gauges, sliders, and more — including a full CodeEditor with syntax highlighting, line numbers, bracket matching, smart indent, and search; no external editor dependency required
• Reactive signals — observable state that flows between widgets; bind once, update everywhere
• Event and stream pipelines — compose, filter, debounce, and throttle UI events with a chainable stream API
• Built-in icons — the full Bootstrap Icons catalog, theme-aware and DPI-scaled, bundled with the framework
• Built-in localization — 23 language catalogs, locale-aware number/date/time formatting, runtime language switching
• Semantic styling — accent="primary", variant="outline" — no hard-coded colors; looks right across every theme automatically
• 8 paired light/dark themes — with a runtime switcher and a custom-theme API
• Forms and validation — field-level validators, inline error messages, and a FormDialog for quick modal forms
• DataSource abstraction — one interface over SQLite, in-memory, and file backends with filtering, sorting, pagination, and CRUD
• A real CLI — scaffold, run, add pages/views/dialogs/themes, and package for distribution
• PyInstaller packaging built in — bootstack build produces a standalone executable; no separate toolchain required

Installation

Requires Python 3.12+ and Tk/Tcl (bundled with most Python distributions). bootstack is in pre-release, so opt in with --pre:

python -m pip install --pre bootstack

See the installation guide for platform-specific Tk setup and the optional data-format extras.

See it

The widget gallery is a single-window tour of everything bootstack ships — every widget, theme switcher, accent variants, and layout containers. Fastest way to see the framework in action without writing a line of code:

bootstack gallery

Quick Start

import bootstack as bs

with bs.App(title="Hello", padding=16, gap=16) as app:
    bs.Label("Hello from bootstack!")
    bs.Button("Primary", accent="primary")
    bs.Button("Success", accent="success")
    bs.Button("Danger Outline", accent="danger", variant="outline")

app.run()

For navigation-based apps, use AppShell — it gives you a command bar, sidebar, and page stack in one call:

import bootstack as bs

shell = bs.AppShell(title="My App", size=(1000, 650))

with shell.add_page("home", text="Home", icon="house"):
    bs.Label("Welcome!")

with shell.add_page("docs", text="Documents", icon="file-earmark-text"):
    bs.Label("Your documents.")

shell.run()

How it works

Layout containers

VStack, HStack, and Grid let you describe a layout once instead of repeating geometry calls on each child:

with bs.App(title="Sign In") as app:
    with bs.Grid(columns=["auto", 1], gap=(12, 6), sticky_items="ew", padding=16):
        bs.Label("Name:")
        bs.TextField(placeholder="Full name")
        bs.Label("Email:")
        bs.TextField(placeholder="email@example.com")
        bs.Label("Role:")
        bs.Select(options=["Admin", "User", "Viewer"], value="User")
        bs.Button("Submit", accent="primary", columnspan=2)

app.run()

Semantic styling

Widgets take an accent (color intent) and variant (visual weight) instead of hard-coded colors, so the same code looks right across themes and light/dark modes:

bs.Button("Save", accent="primary")
bs.Button("Cancel", accent="secondary", variant="outline")
bs.Label("Heading", font="heading-lg")

Signals (optional)

Plain callbacks work fine for most things. When state needs to flow between widgets, signals give you a small reactive primitive with two-way binding:

with bs.App(title="Hello") as app:
    name = bs.Signal("World")
    bs.Label(textsignal=name)      # updates automatically when name changes
    bs.TextField(textsignal=name)  # two-way binding to the same state

app.run()

Features

• Application scaffolding — App for blank windows, AppShell for command-bar + sidebar + page-stack apps, undecorated windows with custom chrome
• 60+ themed widgets — primitives plus higher-level composites (DataTable, Tree, ListView, Calendar, DateField, Form, Gauge, ToggleGroup, PageStack, Carousel, Tooltip, and more)
• Dialogs and messages — alert() / confirm() / ask_*() prompts and FormDialog / FontDialog / FilterDialog, plus non-blocking toast(), Notification, and Snackbar surfaces
• Layout containers — VStack, HStack, and Grid for declarative layouts; Card, GroupBox, ScrollView, SplitView, Accordion, Expander
• Design system — semantic accent colors (primary, secondary, success, danger, warning, info) and variant tokens (solid, outline, ghost), consistent across widgets
• Built-in themes — paired light/dark variants (amber, aurora, bootstrap, classic, docs, forest, ocean, rose) with runtime theme switching and a custom-theme API
• Reactive signals — observable state with subscribe/set, integrates with widgets via signal= / textsignal=
• Forms & validation — Form with built-in field-level validators and inline error messages
• DataSource — common interface over in-memory, SQLite, and file backends, with pagination, filtering, sorting, CRUD, and CSV/TSV/Excel export
• Localization (i18n) — 23 bundled message catalogs, locale-aware number/date/time formatting via Babel, runtime language switching
• Icons & images — Bootstrap Icons catalog with theme-aware recoloring, DPI scaling, and caching
• Platform support — DPI awareness, multi-monitor centering, mica/acrylic effects on Windows
• CLI (bootstack) — project scaffolding, run, add components, theme/i18n setup, doctor, build/package

Widget Categories

Category	Widgets
Actions	Button, ButtonGroup, MenuButton, ContextMenu, CommandBar
Inputs	TextField, PasswordField, PathField, NumberField, SpinnerField, Slider, RangeSlider, TextArea, CodeEditor, DateField, TimeField
Selection	Checkbox, Switch, ToggleButton, Radio, RadioGroup, ToggleGroup, Select, SelectButton, Calendar
Data Display	Label, Badge, ListView, Tree, DataTable, ProgressBar, Gauge
Media	Avatar, Picture, Gallery, Carousel
Layout	VStack, HStack, Grid, Card, GroupBox, SplitView, ScrollView, Accordion, Separator
Navigation	AppShell, CommandBar, SideNav, StatusBar, Tabs, PageStack
Dialogs	alert(), confirm(), ask_*() prompts, FormDialog, FontDialog, FilterDialog
Overlays	toast(), Notification, Snackbar, Tooltip
Forms	Form, with field-level validation

CLI

bootstack ships with an optional CLI for scaffolding, running, and packaging applications:

bootstack gallery                           # Launch the interactive widget gallery
bootstack icons                             # Browse the built-in icon catalog
bootstack start MyApp                       # Create a new project (basic template)
bootstack start MyApp --template appshell   # ...or with sidebar navigation
bootstack run                               # Run the app defined in the project config
bootstack add page Dashboard                # Add a new page (appshell)
bootstack add view Settings                 # Add a new view (basic)
bootstack add dialog Preferences            # Add a new dialog
bootstack add i18n --languages en es fr     # Add i18n support
bootstack doctor                            # Diagnose project & environment
bootstack build                             # Package for distribution

Documentation

Full documentation — guides, the widget catalog, and the API reference — lives at bootstack.org.

Links

• GitHub: https://github.com/israel-dryer/bootstack