⚡ LocalConvert

Free, private file conversion — entirely in your browser.

No account. No upload. No file size limits. Your files never leave your device.

🚀 Try it now → local-converter-bhwl.vercel.app

Why LocalConvert?

You've probably used CloudConvert, Zamzar, or similar tools and run into this:

LocalConvert runs the entire conversion inside your browser using WebAssembly — the same technology that powers browser-based games and desktop-class apps in the browser.

What can it do?

Supported output formats: MP4 · WebM · AVI · MOV · GIF · MP3

Works with most common video and audio inputs: MP4, MOV, MKV, AVI, WebM, and more.

Extra features:

• ✂️ Trim — set a start and end time to extract just the clip you need
• 🎨 High-quality GIF export — two-pass palette encoding, no dithering artifacts
• 📊 Live progress bar — see exactly how far along the conversion is
• 🖱️ Drag & drop — drop a file straight onto the page

How to use it

1. Go to local-converter-bhwl.vercel.app
2. Drop your file or click Browse
3. Pick an output format
4. Optionally set trim start/end times
5. Click Convert — done

No signup, no waiting, no limits.

Supported browsers

Chrome or Edge recommended for best performance.

💛 Support this project

LocalConvert is free and open source. If it saved you time, a small tip means a lot:

• ☕ Buy me a coffee — for international supporters
• 🇮🇳 UPI: your_upi@bank — for Indian users (zero fees)
• ⭐ Star this repo — free and helps others find it

For developers

How it works under the hood

Traditional converters upload your file to a remote server, process it, then send it back. LocalConvert works differently:

Your file → ffmpeg.wasm (runs inside your browser tab) → Converted file
                  ↑
          No server involved

When the page loads, the ffmpeg WebAssembly binary (~30MB) downloads once and is cached by the browser. All subsequent conversions happen entirely on your machine — as fast as your CPU allows.

Tech stack

Run locally

git clone https://github.com/Gokul-Raj-R-Coder/local-converter.git
cd local-converter
npm install
npm run dev

Open http://localhost:5173. Requires Node.js 18+.

The CORS headers required for WebAssembly threading are pre-configured in vite.config.ts for local dev and vercel.json for production.

Deploy your own

Add vercel.json to your project root:

{
  "headers": [
    {
      "source": "/(.*)",
      "headers": [
        { "key": "Cross-Origin-Opener-Policy", "value": "same-origin" },
        { "key": "Cross-Origin-Embedder-Policy", "value": "require-corp" }
      ]
    }
  ]
}

Then run vercel to deploy.

Known limitations

• Files over ~500MB may crash on low-memory devices
• ffmpeg.wasm supports a subset of codecs vs desktop ffmpeg — obscure formats may fail
• Safari restricts SharedArrayBuffer, which can cause slower or failed conversions

Roadmap

• Batch conversion (multiple files at once)
• Quality slider (control output file size)
• Image conversion (HEIC → JPG, AVIF → PNG)
• Desktop app via Tauri (no RAM constraint)

License

MIT — free to fork, modify, and deploy your own version.