Sandbox

Run JavaScript in a Web Worker, safely isolated from the page, and see the output immediately.

Running here in the page — the same app the desktop opens.
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Testing a snippet usually means the browser console, which shares everything with the page you are on. Running it in a worker keeps it in its own context, so an infinite loop is something you can terminate rather than a tab you have to kill.

Console output is captured and displayed, execution is time-limited, and the worker can be stopped at any point. It is the right place to check what a piece of code actually does before trusting it.

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