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Modern Bootstrap 5 components for FastHTML - Build beautiful UIs in pure Python

Project description

FastStrap

Modern Bootstrap 5 components for FastHTML - Build beautiful web UIs in pure Python with zero JavaScript knowledge.

License: MIT Python 3.10+ FastHTML PyPI version Tests


Why FastStrap?

FastHTML is amazing for building web apps in pure Python, but it lacks pre-built UI components. FastStrap fills that gap by providing:

40+ Bootstrap components - Buttons, Cards, Modals, Forms, Navigation, and more
Zero JavaScript knowledge required - Components just work
No build steps - Pure Python, no npm/webpack/vite
Full HTMX integration - Dynamic updates without page reloads
Dark mode built-in - Automatic theme switching
Type-safe - Full type hints for better IDE support
Pythonic API - Intuitive kwargs style ✅ Enhanced customization - Slot classes, CSS variables, themes, and more


Quick Start

Installation

pip install faststrap

Hello World

from fasthtml.common import FastHTML, serve
from faststrap import add_bootstrap, Card, Button, create_theme

app = FastHTML()

# Use built-in theme or create custom
theme = create_theme(primary="#7BA05B", secondary="#48C774")
add_bootstrap(app, theme=theme, theme="dark")

@app.route("/")
def home():
    return Card(
        "Welcome to FastStrap! Build beautiful UIs in pure Python.",
        header="Hello World 👋",
        footer=Button("Get Started", variant="primary")
    )

serve()

That's it! You now have a modern, responsive web app with zero JavaScript.


Enhanced Features

1. Enhanced Attribute Handling

Faststrap now supports advanced attribute handling:

from faststrap import Button

# Style dict and CSS variables
Button(
    "Styled Button",
    style={"background-color": "#7BA05B", "border": "none"},
    css_vars={"--bs-btn-padding-y": "0.75rem", "--bs-btn-border-radius": "12px"},
    data={"id": "123", "type": "demo"},
    aria={"label": "Styled button"},
)

# Filter None/False values automatically
Button("Test", disabled=None, hidden=False)  # None/False values are dropped

2. CloseButton Helper

Reusable close button for alerts, modals, and drawers:

from faststrap import CloseButton, Alert

# Use in alerts
Alert(
    "This alert uses CloseButton helper",
    variant="info",
    dismissible=True,
)

# Use in modals/drawers (automatically used)

3. Expanded Button Component

More control over button appearance and behavior:

from faststrap import Button

# Render as link
Button("As Link", as_="a", href="/page", variant="secondary")

# Loading states with custom text
Button("Loading", loading=True, loading_text="Please wait...", spinner=True)

# Full width, pill, active states
Button("Full Width", full_width=True, variant="info")
Button("Pill", pill=True, variant="warning")
Button("Active", active=True, variant="success")

# Icon and spinner control
Button("Icon + Spinner", icon="check-circle", spinner=True, icon_pos="start")

4. Slot Class Overrides

Fine-grained control over component parts:

from faststrap import Card, Modal, Drawer, Dropdown

# Card with custom slot classes
Card(
    "Content",
    header="Custom Header",
    footer="Custom Footer",
    header_cls="bg-primary text-white p-3",
    body_cls="p-4",
    footer_cls="text-muted",
)

# Modal with custom classes
Modal(
    "Modal content",
    title="Custom Modal",
    dialog_cls="shadow-lg",
    content_cls="border-0",
    header_cls="bg-primary text-white",
    body_cls="p-4",
)

# Drawer with custom classes
Drawer(
    "Drawer content",
    title="Custom Drawer",
    header_cls="bg-success text-white",
    body_cls="p-4",
)

# Dropdown with custom classes
Dropdown(
    "Option 1", "Option 2",
    label="Custom Dropdown",
    toggle_cls="custom-toggle",
    menu_cls="custom-menu",
    item_cls="custom-item",
)

5. Theme System

Create and apply custom themes:

from faststrap import create_theme, add_bootstrap

# Create custom theme
my_theme = create_theme(
    primary="#7BA05B",
    secondary="#48C774",
    info="#36A3EB",
    warning="#FFC107",
    danger="#DC3545",
    success="#28A745",
    light="#F8F9FA",
    dark="#343A40",
)

# Use built-in themes
add_bootstrap(app, theme="green-nature")  # or "blue-ocean", "dark-mode", etc.

# Or use custom theme
add_bootstrap(app, theme=my_theme)

Available built-in themes:

  • green-nature
  • blue-ocean
  • purple-magic
  • red-alert
  • orange-sunset
  • teal-oasis
  • indigo-night
  • pink-love
  • cyan-sky
  • gray-mist
  • dark-mode
  • light-mode

6. Registry Metadata

Components now include metadata about JavaScript requirements:

from faststrap.core.registry import list_components, get_component

# List all components
components = list_components()

# Check if component requires JS
modal = get_component("Modal")
# Modal is registered with requires_js=True

Available Components (38 Total)

✅ Phase 1+2 (v0.1.0 - v0.2.2) - 12 Components

Component Description Status
Button Buttons with variants, sizes, loading states
ButtonGroup Grouped buttons and toolbars
Badge Status indicators and labels
Card Content containers with headers/footers
Alert Dismissible alerts with variants
Modal Dialog boxes and confirmations
Drawer Offcanvas side panels
Toast Auto-dismiss notifications
Navbar Responsive navigation bars
Container/Row/Col Bootstrap grid system
Icon Bootstrap Icons helper

✅ Phase 3 (v0.3.0) - 8 New Components

Component Description Status
Tabs Navigation tabs and pills
Dropdown Contextual menus with split buttons
Input Text form controls with validation
Select Dropdown selections (single/multiple)
Breadcrumb Navigation trail with icons
Pagination Page navigation with customization
Spinner Loading indicators (border/grow)
Progress Progress bars with animations

✅ Phase 4A (v0.4.0) - 10 Components

Component Description Status
Table Responsive data tables
Accordion Collapsible panels
Checkbox Checkbox form controls
Radio Radio button controls
Switch Toggle switch variant
Range Slider input control
ListGroup Versatile lists
Collapse Show/hide content
InputGroup Prepend/append addons
FloatingLabel Animated label inputs

✅ Phase 4B (v0.4.5) - 8 Components

Component Description Status
FileInput File uploads with preview
Tooltip Contextual hints
Popover Rich overlays
Figure Image + caption
ConfirmDialog Modal confirmation preset
EmptyState Placeholder component
StatCard Metric display card
Hero Landing page hero section

🗓️ Phase 5+ (v0.5.0 - v1.0.0)

  • Sidebar, Footer, DashboardLayout
  • DataTable with sorting/filtering/pagination
  • FormWizard, Stepper
  • Timeline, ProfileDropdown, SearchBar
  • Carousel, MegaMenu, NotificationCenter
  • And 40+ more components...

Target: 100+ components by v1.0.0 (Aug 2026)

See ROADMAP.md for complete timeline.


Core Concepts

1. Adding Bootstrap to Your App

from fasthtml.common import FastHTML
from faststrap import add_bootstrap, create_theme

app = FastHTML()

# Basic setup (includes default FastStrap favicon)
add_bootstrap(app)

# With dark theme
add_bootstrap(app, theme="dark")

# Custom theme
theme = create_theme(primary="#7BA05B", secondary="#48C774")
add_bootstrap(app, theme=theme)

# Using CDN
add_bootstrap(app, use_cdn=True)

2. Using Components

All components follow Bootstrap's conventions with Pythonic names:

from faststrap import Button, Badge, Alert, Input, Select, Tabs

# Button with HTMX
Button("Save", variant="primary", hx_post="/save", hx_target="#result")

# Form inputs
Input("email", input_type="email", label="Email Address", required=True)
Select("country", ("us", "USA"), ("uk", "UK"), label="Country")

# Navigation tabs
Tabs(
    ("home", "Home", True),
    ("profile", "Profile"),
    ("settings", "Settings")
)

3. HTMX Integration

All components support HTMX attributes:

# Dynamic button
Button("Load More", hx_get="/api/items", hx_swap="beforeend")

# Live search input
Input("search", placeholder="Search...", hx_get="/search", hx_trigger="keyup changed delay:500ms")

# Dynamic dropdown
Select("category", ("a", "A"), ("b", "B"), hx_get="/filter", hx_trigger="change")

4. Responsive Grid System

from faststrap import Container, Row, Col

Container(
    Row(
        Col("Left column", cols=12, md=6, lg=4),
        Col("Middle column", cols=12, md=6, lg=4),
        Col("Right column", cols=12, md=12, lg=4)
    )
)

Examples

Form with Validation

from faststrap import Input, Select, Button, Card

Card(
    Input(
        "email",
        input_type="email",
        label="Email Address",
        placeholder="you@example.com",
        required=True,
        help_text="We'll never share your email"
    ),
    Input(
        "password",
        input_type="password",
        label="Password",
        required=True,
        size="lg"
    ),
    Select(
        "country",
        ("us", "United States"),
        ("uk", "United Kingdom"),
        ("ca", "Canada"),
        label="Country",
        required=True
    ),
    Button("Sign Up", variant="primary", type="submit", cls="w-100"),
    header="Create Account"
)

Navigation with Tabs

from faststrap import Tabs, TabPane, Card

Card(
    Tabs(
        ("profile", "Profile", True),
        ("settings", "Settings"),
        ("billing", "Billing")
    ),
    Div(
        TabPane("Profile content here", tab_id="profile", active=True),
        TabPane("Settings content here", tab_id="settings"),
        TabPane("Billing content here", tab_id="billing"),
        cls="tab-content p-3"
    )
)

Loading States

from faststrap import Spinner, Progress, Button

# Spinner in button
Button(
    Spinner(size="sm", label="Loading..."),
    " Processing...",
    variant="primary",
    disabled=True
)

# Progress bar
Progress(75, variant="success", striped=True, animated=True, label="75%")

# Stacked progress
Div(
    ProgressBar(30, variant="success"),
    ProgressBar(20, variant="warning"),
    ProgressBar(10, variant="danger"),
    cls="progress"
)

Pagination

from faststrap import Pagination, Breadcrumb

# Breadcrumb
Breadcrumb(
    (Icon("house"), "/"),
    ("Products", "/products"),
    ("Laptops", None)
)

# Page navigation
Pagination(
    current_page=5,
    total_pages=20,
    size="lg",
    align="center",
    show_first_last=True
)

Project Structure

faststrap/
├── src/faststrap/
│   ├── __init__.py              # Public API
│   ├── core/
│   │   ├── assets.py            # Bootstrap injection + favicon
│   │   ├── base.py              # Component base classes
│   │   ├── registry.py          # Component registry
│   │   └── theme.py             # Theme system
│   ├── components/
│   │   ├── forms/               # Button, Input, Select
│   │   ├── display/             # Card, Badge
│   │   ├── feedback/            # Alert, Toast, Modal, Spinner, Progress
│   │   ├── navigation/          # Navbar, Drawer, Tabs, Dropdown, Breadcrumb, Pagination
│   │   └── layout/              # Container, Row, Col
│   ├── static/                  # Bootstrap assets + favicon
│   │   ├── css/
│   │   │   ├── bootstrap.min.css
│   │   │   └── bootstrap-icons.min.css
│   │   ├── js/
│   │   │   └── bootstrap.bundle.min.js
│   │   └── favicon.svg          # Default FastStrap favicon
│   ├── templates/               # Component templates
│   └── utils/
│       ├── icons.py             # Bootstrap Icons
│       ├── static_management.py # Assets extended helper functions
│       └── attrs.py             # Centralized attribute conversion
├── tests/                       # 219 tests (80% coverage)
├── examples/                    # Demo applications
│   └── demo_all.py              # Comprehensive demo
└── docs/                        # Documentation

Development

Prerequisites

  • Python 3.10+
  • FastHTML 0.6+
  • Git

Setup

# Clone repository
git clone https://github.com/Faststrap-org/Faststrap.git
cd Faststrap

# Create virtual environment
python -m venv .venv
source .venv/bin/activate  # Windows: .venv\Scripts\activate

# Install with dev dependencies
pip install -e ".[dev]"

# Run tests
pytest

# Run with coverage
pytest --cov=faststrap

# Type checking
mypy src/faststrap

# Format code
black src/faststrap tests
ruff check src/faststrap tests

Contributing

We welcome contributions! See CONTRIBUTING.md for guidelines.

Quick Contribution Guide

  1. Pick a component from ROADMAP.md Phase 4
  2. Follow patterns in BUILDING_COMPONENTS.md
  3. Write tests - Aim for 100% coverage (8-15 tests per component)
  4. Submit PR - We review within 48 hours

Documentation


Roadmap

v0.3.1 (Current - December 2025)

  • ✅ 20 components (12 + 8 new)
  • ✅ 219 tests, 80% coverage
  • ✅ Centralized convert_attrs() utility
  • ✅ Default FastStrap favicon
  • ✅ Full HTMX integration
  • ✅ Enhanced customization (slot classes, CSS vars, themes)
  • ✅ Component defaults system with resolve_defaults()

v0.4.0 (Phase 4A - Complete)

  • ✅ Table, Accordion, Checkbox, Radio, Switch
  • ✅ Range, ListGroup, Collapse, InputGroup, FloatingLabel
  • ✅ 30 components total

v0.4.5 (Phase 4B - Complete)

  • ✅ FileInput, Tooltip, Popover, Figure
  • ✅ ConfirmDialog, EmptyState, StatCard, Hero
  • ✅ 38 components total

v0.5.0 (Phase 5 - Mar 2026)

  • Sidebar, Footer, DashboardLayout
  • Timeline, Carousel, MegaMenu
  • 50 components total

v1.0.0 (Target Aug 2026)

  • 100+ components
  • Component playground
  • Full documentation website
  • Video tutorials
  • Production ready

See ROADMAP.md for complete timeline.


Stats

  • 38 components across 5 categories
  • 219+ passing tests
  • Zero custom JavaScript required
  • Full HTMX integration
  • Enhanced customization with slot classes, CSS variables, and themes

Support


License

MIT License - see LICENSE file for details.


Acknowledgments

  • FastHTML - The amazing pure-Python web framework
  • Bootstrap - Battle-tested UI components
  • HTMX - Dynamic interactions without complexity
  • Contributors - Thank you! 🙏

Built with ❤️ for the FastHTML community

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