Record any browser tab, window, or your screen — including audio — and save it as an MP4. No app to install, no account, nothing ever leaves your browser.
Browsers only record video natively as WebM, not MP4. Rather than upload your recording to a server to convert it — which would mean your screen recording briefly leaving your device — Thunder Video Downloader runs a real video encoder (ffmpeg, compiled to WebAssembly) directly in your browser. It's slower than a server with dedicated hardware would be, so it works best for short clips at 720p or lower — 5 minutes or under, no higher than 720p. Longer or higher-resolution recordings take proportionally longer, but nothing about what you recorded ever has to leave your computer.
A screen recording is often the fastest way to show someone exactly what happened — this exists for the moments a written explanation would take three times as long.
Open Thunder Video Downloader, click the share button, then pick the tab, window, or screen in your browser's own sharing dialog — check "Share tab audio" or "Share system audio" if you want sound in the recording. Once the source is ready, click Start Recording.
MP4 (H.264 video, AAC audio), converted locally in your browser right after you stop recording — no server-side conversion, and no separate app or upload step.
No. Recording and MP4 conversion both happen locally in your browser (the conversion uses ffmpeg compiled to WebAssembly). Nothing is sent to a server — the file only exists on your device until you download it.
Browsers only record video as WebM natively, so converting to MP4 requires real video encoding, done entirely on your own device rather than a server. It works best for short clips at 720p or lower — 5 minutes or under, no higher than 720p, converts in a reasonable amount of time. Longer or higher-resolution recordings take proportionally longer — keep the tab open until it finishes.
Yes, completely free, no account or install required.
Only whatever your browser's own sharing dialog offers — typically a full tab, full window, or full screen. A custom partial-region selection isn't part of that browser API.
It captures tab or system audio, depending on what you share — microphone input isn't included unless your own system audio setup routes it in separately.
The recording is lost — keep the tab open and active until you've clicked Stop and downloaded the file.