CastLens
No upload No signup Free to use

Free Online Screen Recorder

Record your screen, an app window, or a browser tab — right in your browser. The video never leaves your device.

MP4
00:00 Ready

Click Record — you'll pick a screen, window, or tab in the browser prompt.

How it works

1

Choose what to capture

Click Record, then pick a screen, an app window, or a Chrome tab in the browser prompt.

2

Record with optional audio

Toggle your microphone or system audio before you start. Pause and resume any time.

3

Save the video file

Stop the recording, preview it, and download the file — MP4 on modern browsers.

Good to know

MP4 or WebM?

Chrome 126+, Edge and Safari record MP4 (H.264) directly — ready for WeChat, Bilibili, YouTube and any platform. Firefox saves WebM, which most platforms also accept.

System audio on macOS

macOS allows system-audio capture on Chrome 141+ with macOS 14.2+. On older versions, share a Chrome tab instead — the tab's sound is always captured. Windows supports system audio.

Private by design

Recording runs entirely inside your browser. The video is saved straight to your device and never uploaded to any server — there isn't even a server.

Limits you can't bypass

DRM-protected video (Netflix and similar) records as black. The browser also shows a "sharing" indicator while recording — it can't be hidden.

FAQ

Is CastLens free?

Yes — free to use, no signup, no watermark, no time limit.

Where does my video go?

Nowhere. Recording happens entirely inside your browser and the file is saved straight to your device. Nothing is uploaded to any server.

Can I record system audio on macOS?

Yes on Chrome 141 or newer with macOS 14.2+. On older versions, macOS only allows tab audio — share a Chrome tab and its sound will be captured. Windows supports system audio.

Will I get an MP4 file?

On Chrome 126+, Edge, and Safari the recording is saved as MP4 (H.264), ready for any platform. Firefox saves WebM — most platforms accept it, or convert it to MP4 afterwards.

Which browsers and devices are supported?

Desktop Chrome, Edge, Brave, Safari 16+, and Firefox. Mobile browsers don't allow screen sharing, so CastLens needs a desktop browser.

Why wasn't I asked for screen recording permission?

macOS asks for Screen Recording permission once per browser app and never again — if that single prompt was missed or dismissed, capture fails silently. Open System Settings → Privacy & Security → Screen Recording, enable your browser, and fully restart it.