Paste your TradingView Pine Script and find out instantly. We check for the exact mechanics behind repainting and look-ahead bias — the reason a backtest can look better than the strategy ever trades.
Code-correctness check only — not financial advice, not a measure of profitability. Conservative static analysis; always chart and test your script yourself.
barstate.isconfirmed gate, so it can flip before the bar closes.request.security() with barmerge.lookahead_on and no [1] offset, which stamps historical bars with a value they couldn't have known live.varip and timenow, which can't be reproduced on historical bars.calc_on_every_tick=true strategies that evaluate mid-bar live but on close in the tester.Educational, code-correctness analysis only — not financial advice, and not a measure of profitability. Trading involves substantial risk of loss.
Paste it above and click Check. The tool scans for the mechanics that cause repainting — signals read from the still-forming bar without a barstate.isconfirmed gate, higher-timeframe request.security() calls without a [1] offset, look-ahead via barmerge.lookahead_on, and varip/timenow state — and lists each with the exact fix.
Repainting is when a script shows one thing on historical bars and a different thing in real time — a signal that appears mid-bar and then vanishes when the bar closes, or a higher-timeframe value that 'knows the future' on history but not live. It makes a backtest look better than the strategy would trade, so it's a correctness bug worth catching before you rely on the script.
Yes — it runs entirely in your browser with no login and no limit. It's deterministic static analysis, so it never sends your code anywhere. The full Strategy Validator (with a Strategy Health Score, deeper analysis and a shareable badge) is the paid step after two free runs.
No. This checks code correctness only — whether the script behaves consistently between the tester and live. It is not financial advice and says nothing about profitability. Trading involves substantial risk of loss.