VidKit

Free, browser-based video tools that never upload your files. Compress and convert video entirely on your own device — there is no server, so your footage never leaves your machine.

🔗 Live: https://vidkit.eu

A 36 MB clip compressed to a target size in seconds, on-device via WebCodecs. Try it at vidkit.eu/compress-video.

Why it's private

Every other "online video compressor" uploads your video to a server, processes it there, and sends it back. VidKit doesn't have a server that could receive your file. All processing runs locally in your browser:

• Zero file upload. Not the bytes, not the filename, not the size — nothing about your file is ever transmitted. You can verify it yourself: open your browser's Network tab while compressing and watch it stay silent.
• No cookies, no cross-site tracking, no accounts. The only data collected is cookieless, aggregate page-view counts (Umami) — never anything about your files.
• No watermarks, no sign-up, no file-count limits.
• This guarantee is enforced by an automated test (e2e/privacy.spec.ts): any request to a non-allowlisted host, or any request carrying a body, fails the build.

What it does

• Compress video to an exact file size (e.g. 25 MB for email, 10 MB for Discord, 16 MB for WhatsApp) or to a quality level.
• Convert between formats: MP4, MOV, MKV, WebM, plus audio extraction to MP3 / M4A and animated GIF.
• Side-by-side before/after preview before you download.
• English and Czech, with a non-intrusive language suggestion (no auto-redirect).
• A maintained reference of video upload size limits for every platform (Discord, WhatsApp, Gmail, TikTok, …), verified against official docs.

How it works

• WebCodecs API does the heavy lifting where available — hardware- accelerated, often faster than the video plays.
• ffmpeg.wasm is a lazy-loaded fallback for formats/codecs WebCodecs can't handle (WebM, MP3, GIF, AVI input). The ~9.7 MB core is only fetched when actually needed.
• mediabunny handles fast container parsing and muxing.

Tech

Vanilla TypeScript + Vite. No framework, plain CSS with custom properties. Ships as a fully static site (hosted on Cloudflare Pages). Every tool is its own static, crawlable HTML page.

Develop

Requires Node 22 (see .nvmrc).

npm install        # also fetches + gzips the ffmpeg core (postinstall)
npm run dev        # http://localhost:5173
npm run build      # type-check + production build into dist/
npm run preview    # serve the production build

Test

npm run test:unit  # pure-logic unit tests (Node test runner)
npm run test:e2e   # Playwright: compression, conversion, and the privacy audit

Third-party notices

• ffmpeg.wasm (@ffmpeg/core) is licensed under the GPL/LGPL; it is a separate dependency fetched via npm and served as-is. Its source is available from the ffmpeg.wasm project.
• mediabunny and other dependencies retain their respective licenses.

VidKit's own source code is licensed under the MIT License — see LICENSE.