Convert any file,
right in your browser.
Images, video, audio, documents, and PDFs — converted locally on your device. No upload, no tracking, no account. Your files never leave the browser.
Privacy-first · No account · Open source
Features
Built for speed, privacy, and zero friction.
Every conversion runs locally in your browser. No server, no wait, no file size limit dictated by us.
100% in-browser
Every byte is processed by WebAssembly running on your CPU. Open DevTools and watch it work.
No upload, no tracking
Your files never touch a server. We can't see them, and neither can anyone else.
Images, video, docs, PDF
The formats you actually use, in one workspace. No install, no plugin.
Mobile-friendly
Drop in a file from your phone's photo library, convert, share. Works offline once loaded.
Open source
MIT licensed. Audit the code, fork it, self-host it. Built on the shoulders of mammoth, marked, pdf-lib, and ffmpeg.wasm.
Free forever
No premium tier, no watermark, no "upgrade to remove limits". Convert all day, every day.
Formats
— formats in your browser.
More in the self-hosted edition.
The browser can do a lot — but not everything. If you need a format we don't cover here, the original ConvertX self-hosts over 1,000 formats.
Images
Convert and compress between common image formats.
Video & Audio
Transcode video and audio with FFmpeg running in your browser.
Documents
Convert DOCX and Markdown to HTML and PDF.
Merge, split, and generate PDFs from HTML.
How it works
Three steps. Zero servers.
-
01
Drop your file
Drag-and-drop or click to browse. The file is read directly by your browser's File API.
-
02
Pick the target format
Choose the format you want from a focused picker — no nested menus, no jargon.
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03
Download the result
The converted file is generated as a Blob and saved to your device. No intermediate storage.
Privacy by design
Your files never leave this tab.
ConvertX runs entirely on your device using WebAssembly. There's no backend. There's no upload. There's no analytics on your file contents. Open the Network tab — every request is for static assets only.
▸ Loaded: /index.html
▸ Loaded: /convert.html
▸ Loaded: /core/ffmpeg-core.wasm
// No network requests during conversion.
// Conversion runs in WebAssembly sandbox.
// File contents stay in browser memory.
✓ Privacy verified.
"I needed to convert a quick MP4 to MP3 for a podcast edit. Did it on my phone over coffee — no app, no sign-up, no upload bar. Just worked."
FAQ