Convert UI

A modern, browser-based file conversion application built with Next.js 16, Tailwind CSS 4, and WebAssembly. Convert videos, images, and documents directly in your browser without uploading files to any server.

Features

• 🎬 Video Conversion - Convert between MP4, WebM, AVI, MOV, MKV, and GIF
• 🎵 Audio Conversion - Convert between MP3, WAV, OGG, AAC, and FLAC
• 🖼️ Image Conversion - Convert between PNG, JPG, WebP, GIF, BMP, TIFF, and SVG
• 📄 Document Conversion - Convert between Markdown, HTML, and Plain Text
• 🔒 Privacy First - All conversions happen locally in your browser, no server uploads
• ⚡ Fast & Efficient - Powered by WebAssembly for near-native performance
• 🎨 Beautiful UI - Modern, responsive design with dark/light theme support
• 🔍 Smart Search - Fuzzy search for quick format selection
• 📝 Conversion History - Track your recent conversions
• 🎯 Drag & Drop - Easy file upload with drag-and-drop support

Tech Stack

• Next.js 16 - React framework with App Router and static export
• React 19 - Latest React with concurrent features
• TypeScript 5 - Type-safe development
• Tailwind CSS 4 - Utility-first CSS with OKLCH color system
• FFmpeg.wasm - Video and audio conversion
• ImageMagick WASM - Image processing and conversion
• Marked - Markdown to HTML conversion
• Turndown - HTML to Markdown conversion
• DOMPurify - HTML sanitization
• Fuse.js - Fuzzy search for format selection
• Lucide React - Beautiful icon library

Getting Started

Prerequisites

• Node.js 22+ (managed via nvm)
• pnpm (enabled via corepack)

Installation

# Clone the repository
git clone <repository-url>
cd convert-ui

# Install dependencies
pnpm install

# Run development server
pnpm dev

Open http://localhost:3000 to view the app.

Build for Production

# Build static export
pnpm build

# Output will be in the /out directory

Project Structure

convert-ui/
├── app/                              # Next.js App Router
│   ├── layout.tsx                   # Root layout with theme
│   ├── page.tsx                     # Main page
│   └── globals.css                  # Global styles
├── components/
│   ├── converter/                   # Converter components
│   │   ├── FileConverter.tsx        # Main state manager
│   │   ├── FileUpload.tsx          # Drag-and-drop upload
│   │   ├── FormatSelector.tsx      # Format selection with search
│   │   ├── ConversionPreview.tsx   # Preview and download
│   │   └── ConversionOptions.tsx   # Format-specific options
│   ├── layout/
│   │   └── ThemeToggle.tsx         # Dark/light theme toggle
│   └── ui/                         # Reusable UI components
│       ├── Button.tsx
│       ├── Card.tsx
│       ├── Toast.tsx
│       ├── Progress.tsx
│       ├── Skeleton.tsx
│       └── Input.tsx
├── lib/
│   ├── converters/                 # Conversion services
│   │   ├── ffmpegService.ts       # Video/audio conversion
│   │   ├── imagemagickService.ts  # Image conversion
│   │   └── pandocService.ts       # Document conversion (placeholder)
│   ├── wasm/
│   │   └── wasmLoader.ts          # WASM module lazy loading
│   ├── storage/
│   │   └── history.ts             # Conversion history
│   └── utils/
│       ├── cn.ts                  # Class name utility
│       ├── fileUtils.ts           # File operations
│       ├── formatMappings.ts      # Supported formats
│       └── debounce.ts            # Debounce utility
└── types/
    └── conversion.ts              # TypeScript interfaces

Supported Formats

Video (FFmpeg)

• Input/Output: MP4, WebM, AVI, MOV, MKV, GIF

Audio (FFmpeg)

• Input/Output: MP3, WAV, OGG, AAC, FLAC

Images (ImageMagick)

• Input/Output: PNG, JPG, WebP, GIF, BMP, TIFF, SVG

Documents

• Markdown → HTML - Full GitHub Flavored Markdown support with styling
• HTML → Markdown - Clean conversion with formatting preservation
• Markdown ↔ Plain Text - Strip or add basic formatting
• HTML → Plain Text - Extract text content
• Plain Text → HTML - Convert to formatted HTML document

Note: Uses lightweight JavaScript libraries (marked, turndown) instead of Pandoc WASM for fast, reliable conversions.

How It Works

1. File Upload - Users can drag-and-drop or click to select a file
2. Format Detection - The app automatically detects the input format
3. Format Selection - Choose from compatible output formats
4. Conversion - WASM modules are loaded on-demand and process the file
5. Download - Preview and download the converted file

WASM Architecture

• Lazy Loading - WASM modules are only loaded when needed
• Memory Management - Proper cleanup after each conversion
• Progress Tracking - Real-time progress updates during conversion
• Error Handling - Graceful error handling with user-friendly messages

Browser Compatibility

• Chrome/Edge - Full support
• Firefox - Full support
• Safari - Full support (with SharedArrayBuffer)

Note: Some features require SharedArrayBuffer support. The app sets the required COOP/COEP headers for this.

Performance

• File Size Limit - 500MB (configurable)
• Conversion Speed - Varies by file size and format
  • Images: < 5s for typical files
  • Videos: Depends on length and quality
• Memory Usage - Managed automatically with cleanup

Development

Scripts

# Development server with Turbopack
pnpm dev

# Build for production
pnpm build

# Run production server
pnpm start

# Lint code
pnpm lint

Adding New Formats

1. Add format to lib/utils/formatMappings.ts
2. Implement converter in appropriate service
3. Update type definitions in types/conversion.ts

Customizing Theme

Colors are defined in app/globals.css using OKLCH color space. Modify CSS variables to change the theme:

:root {
  --primary: oklch(22.4% 0.053 285.8);
  --background: oklch(100% 0 0);
  /* ... other colors */
}

Docker Deployment

# Build Docker image
docker build -t convert-ui .

# Run container
docker run -p 80:80 convert-ui

The Dockerfile uses a multi-stage build with Nginx to serve the static export.

Contributing

Contributions are welcome! Please follow these steps:

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Test thoroughly
5. Submit a pull request

License

MIT License - See LICENSE file for details

Acknowledgments

• FFmpeg.wasm - Video/audio conversion
• ImageMagick WASM - Image processing
• Next.js - React framework
• Tailwind CSS - Styling
• Fuse.js - Fuzzy search

Support

For issues, questions, or suggestions, please open an issue on GitHub.

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Made with ❤️ using Next.js 16 and WebAssembly