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Design your scripts around these limits.

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Execution budget

Each run of compute has a 1000 ms budget. A script that exceeds it is disabled until you edit it. Keep loops proportional to the number of bars and avoid rescanning the whole series for every bar.

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Synchronous only

No async, fetch or timers. compute must return its result directly.

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Sandbox

Scripts run isolated from the terminal page. There is no window, document, storage, network access, eval, new Function or import(). Only plain JavaScript built-ins, console and performance.now() are available. Intl.DateTimeFormat works for time zone math. Return plain data: numbers, strings, arrays and objects.

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No persistence

Nothing is kept between runs. Model “current state” by replaying your rules over the series inside compute. See the signal engine example.

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Caps

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History depth

A script sees the bars the chart has loaded. By default that is about: Panning back loads more history and re-runs the script.

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Not supported

  • Restyling the main price series (Pine plotcandle and barcolor).
  • Filling between two plots (Pine fill). Plot the two boundaries, or draw boxes.
  • Alerts from scripts (Pine alertcondition). Price alerts are a separate terminal feature.