faststrap 0.5.2

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

FastStrap

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

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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:

✅ 51 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
✅ Zero-JS animations - Beautiful effects with pure CSS (Fx module)
✅ 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
✅ 95% documented - Comprehensive docs with examples

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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.

Working with Static Files

Faststrap V0.5.1+ includes a helper to easily mount your own static files (images, CSS, etc.):

from faststrap import mount_assets

# Mount your "assets" directory at "/assets" URL
mount_assets(app, "assets")

# Use in your app
Img(src="/assets/logo.png")
Div(style="background-image: url('/assets/hero.jpg')")

See Static Files Guide for more details.

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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

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Available Components (51 Total)

All components are production-ready with comprehensive documentation, HTMX integration, and accessibility features.

Forms (13 Components)

• Button - Buttons with variants, sizes, loading states, icons
• CloseButton - Reusable close button for dismissible components
• ButtonGroup - Grouped buttons and toolbars
• ButtonToolbar - Multiple button groups
• Input - Text inputs with validation and types
• Select - Dropdown selections with multiple options
• Checkbox - Checkboxes with inline/stacked layouts
• Radio - Radio buttons with groups
• Switch - Toggle switches
• Range - Range sliders
• FileInput - File upload inputs
• InputGroup - Input addons (text, buttons, icons)
• FloatingLabel - Animated floating labels

Display (10 Components)

• Card - Content containers with headers/footers/images
• Badge - Status indicators and labels
• Table - Data tables with striped, hover, bordered styles
• Figure - Images with captions
• Icon - Bootstrap Icons helper (2,000+ icons)
• EmptyState - Empty state placeholders
• StatCard - Statistics display cards
• Image - Responsive images with fluid, thumbnail, rounded, alignment
• Carousel - Auto-play image sliders with controls, indicators, fade
• Placeholder - Skeleton loading with glow/wave animations

Feedback (10 Components)

• Alert - Dismissible alerts with variants
• Modal - Dialog boxes and confirmations
• ConfirmDialog - Pre-configured confirmation modals
• Toast - Auto-dismiss notifications
• SimpleToast - Quick toast helper
• ToastContainer - Toast positioning container
• Spinner - Loading indicators (border/grow)
• Progress - Progress bars with stripes/animation
• ProgressBar - Individual progress bar component
• Tooltip - Hover tooltips
• Popover - Click popovers
• Collapse - Show/hide content areas

Navigation (14 Components)

• Navbar - Responsive navigation bars
• NavbarModern - Glassmorphism navbar
• Tabs - Navigation tabs and pills
• TabPane - Tab content panes
• Dropdown - Contextual dropdown menus
• DropdownItem - Dropdown menu items
• DropdownDivider - Dropdown separators
• Breadcrumb - Navigation breadcrumbs
• Pagination - Page navigation
• Accordion - Collapsible panels
• AccordionItem - Individual accordion panels
• ListGroup - Versatile content lists
• ListGroupItem - List items with badges/variants
• Drawer - Offcanvas side panels
• Scrollspy - Auto-updating navigation based on scroll
• SidebarNavbar - Premium vertical sidebar for dashboards
• GlassNavbar - Premium glassmorphism navbar

Layout (4 Components)

• Container - Responsive containers (fixed/fluid)
• Row - Grid rows with gutters
• Col - Grid columns with breakpoints
• Hero - Hero sections with backgrounds/overlays

Layouts (2 Composed Layouts)

• DashboardLayout - Admin panel with sidebar
• LandingLayout - Marketing page layout

Effects (1 Module)

• Fx - Zero-JS animations and visual effects
  • Entrance animations (fade, slide, zoom, bounce)
  • Hover interactions (lift, scale, glow, tilt)
  • Loading states (spin, pulse, shimmer)
  • Visual effects (glass, shadows, gradients)
  • Speed and delay modifiers

Patterns (5 Composed Components)

• Feature - Feature highlight component
• FeatureGrid - Grid of features
• PricingTier - Pricing card component
• PricingGroup - Group of pricing tiers

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Documentation Coverage

• 95% documented (43/45 components)
• All docs include:
  • Bootstrap CSS class guides
  • HTMX integration examples
  • set_component_defaults usage
  • Responsive design patterns
  • Accessibility best practices
  • Common recipes and patterns

View docs: https://faststrap-org.github.io/Faststrap/

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Examples

Comprehensive examples organized by learning path:

01_getting_started/

• hello_world.py - Your first Faststrap app
• first_card.py - Working with components
• simple_form.py - Building forms
• adding_htmx.py - HTMX interactivity

03_real_world_apps/

• blog/ - Complete blog with posts, comments, admin
• calculator/ - HTMX-powered calculator
• game/ - Tic-tac-toe with win detection
• ecommerce/ - E-commerce store (existing)

04_advanced/

• effects_showcase.py - All Faststrap effects demo
• custom_themes.py - Theme customization
• component_defaults.py - Global configuration

See: examples/README.md for complete guide

| 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.

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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)
    )
)

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Examples

Form with Validation

from faststrap import Input, Select, Button, Card

Card(
    Input(
        "email",
        input_type="email",
        label="Email Address",
        placeholder="[e-mail]",
        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
)

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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

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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

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Troubleshooting

Static Files Not Loading (404 Errors)

Fixed in v0.4.6+! If you're seeing 404 errors for Bootstrap CSS/JS files, update to the latest version:

pip install --upgrade faststrap

Theme Not Applied with fast_app()

When using fast_app(), add data_bs_theme to your root element:

app, rt = fast_app()
add_bootstrap(app, mode="light")

@rt("/")
def get():
    return Div(
        YourContent(),
        data_bs_theme="light",  # ← Add this for proper theming
    )

Styles Not Loading with Custom Html()

When manually creating Html() + Head(), include *app.hdrs:

@app.route("/")
def get():
    return Html(
        Head(
            Title("My App"),
            *app.hdrs,  # ← Required for Faststrap styles
        ),
        Body(YourContent())
    )

For more help, see TROUBLESHOOTING.md

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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

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Documentation

• 📖 Component Spec: COMPONENT_SPEC.md
• 🏗️ Building Guide: BUILDING_COMPONENTS.md
• 🗺️ Roadmap: ROADMAP.md
• 🤝 Contributing: CONTRIBUTING.md
• 📝 Changelog: CHANGELOG.md

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Troubleshooting

Static Files Not Loading (404 Errors)

Problem: Background images or custom assets return 404 Not Found.

Solution: Use mount_assets() to properly mount your static directory:

from faststrap import mount_assets

mount_assets(app, "assets")  # Mounts assets/ at /assets/

Then reference files with the correct path:

Div(style="background-image: url('/assets/hero-bg.jpg')")  # ✅ Correct
Div(style="background-image: url('/hero-bg.jpg')")         # ❌ Wrong

See Static Files for full guide.

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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.

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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

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Support

• 📖 Documentation: GitHub README
• 🐛 Bug Reports: GitHub Issues
• 💬 Discussions: GitHub Discussions
• 🎮 Discord: FastHTML Community

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License

MIT License - see LICENSE file for details.

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Acknowledgments

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

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Built with ❤️ for the FastHTML community