Screen Recorder

The Screen Recorder uses your browser's built-in screen sharing to record your whole screen, one window, or one browser tab, and gives you a .webm video you can preview and download. It suits recording a walkthrough, reproducing a problem, or narrating while you work. It is a very basic recorder: there is no pause button, no countdown, no setting for resolution, frame rate, or bitrate, no editing, and the output is WebM by default (or the browser's supported format if WebM is unavailable), never converted afterwards.

How to use it

1. If you want to narrate, first tick 'Also record microphone audio (useful for narrating while screen-recording)'. The option is greyed out once recording starts.
2. Click 'Start Recording'. The browser opens its own share picker where you choose the entire screen, a window, or a browser tab. If you ticked the microphone option, it also asks for microphone permission.
3. Once recording begins, the page shows a red 'Recording…' notice. Switch to whatever you want to record and carry on.
4. To finish, come back and click 'Stop Recording', or use the browser's own 'Stop sharing' button. Either ends the recording.
5. A video player appears. Play it back, and if it is fine click 'Download Recording (.webm)'. The file is named screen-recording.webm (the extension follows the format if the browser falls back to another one).

A usage scenario

Suppose you want to show a colleague the steps in an admin system. Tick the microphone option, click 'Start Recording', choose that browser tab in the share picker, explain out loud as you click through, then stop, replay to check, and download to send. Quality, frame rate, and file size are all decided by the browser, and the code gives no options for them, so we do not quote file-size or frame-rate figures. Choosing a single tab rather than the entire screen avoids recording private information in other windows.

Supported input and known limits

• The browser must support the screen-sharing interface. If it does not, the page shows a notice: 'Your current browser doesn't support screen recording. Please try again using the latest version of Chrome, Edge, or Firefox.' Phone browsers generally do not support it.
• The code prefers WebM; if the browser does not support it (Safari, for example), it falls back to a format the browser supports, such as MP4, and the download extension and button label change accordingly. If starting still fails, the message 'Couldn't start recording. You may have cancelled the screen-share permission, or your browser doesn't support this feature.' appears, and it does not distinguish a cancelled permission from other causes.
• Whether computer or tab audio is captured depends on the browser, the operating system, and what you tick in the share picker. Without the right option, the recording may have no sound.
• With the microphone option and shared computer audio, the code mixes both into one audio track before recording; if the browser cannot mix, it falls back to two separate tracks, and some browsers may then keep only one. Record a short test and play it back before an important session to check your voice is there.
• There is no pause or resume, and no warning about length. Data is held in memory while recording, so a long recording can use a lot of memory.
• The resulting WebM often lacks complete duration information, so seeking can be awkward in some players. For a more universal format, convert it with another tool.
• If microphone permission is denied or fails after screen sharing has started, the code stops the screen share automatically and shows the error message.
• It records exactly what you select. The page does not blur or hide private content, so close notifications and windows you do not want recorded before you start.

FAQ: Why can't it record the whole screen automatically? I have to pick every time.

That is a browser privacy rule: a web page must let you choose what to share each time, and cannot bypass it. The page cannot record your screen silently.

FAQ: My recording has no sound. What should I do?

Make sure you ticked the microphone option and allowed the permission. To capture sound from the computer, tick the option to share audio in the share picker (some browsers only offer this when sharing a tab). Recording a few seconds first and playing them back is the safest check.

FAQ: Can I get an MP4?

This tool normally outputs WebM (browsers without WebM support output their own format) and does no conversion. To get MP4, use one of the site's video tools or other software to convert the WebM.

FAQ: Is the recording uploaded to a server?

No. The code has no upload logic, and the recording lives only in your browser's memory. Details are below.

Privacy and processing

Recording happens entirely in your browser. The code uses the browser's screen-sharing and MediaRecorder interfaces, keeps the data chunks in memory, assembles one video when you stop, and offers it through a temporary local link for preview and download. There is no network request that sends the picture or sound to a server. The recording disappears when you refresh or close the page, so download it promptly. When you leave the page the code tries to stop any recording in progress and shut down the screen and microphone streams.