Plotted alongside the candles
The strategy’s P&L is rendered as a line over the same chart, so wins and losses sit visibly next to the bars that produced them. No tab-switching to a separate report screen.
//BACKTESTER · WEB WORKER · JS
Backtest in JavaScript,
in the tab.
The backtester accepts a JavaScript strategy and runs it over the bars currently loaded into the chart, inside a sandboxed Web Worker that can’t reach the network or the rest of the page. The result — equity curve, trade list, max drawdown, win rate, fill rate — is rendered alongside the candles. Free, browser-based, no upload.
- Language
- JavaScript
- Sandbox
- Web Worker
- Data
- Binance OHLCV
- Cost
- $0
What you get back
Every entry, exit, and result
A row per round-trip: entry timestamp, exit timestamp, side, P&L absolute, P&L percent, hold duration. Sortable, exportable to CSV, copyable into a journal.
Max drawdown, win rate, fill rate
The summary bar reports the metrics you actually act on: peak-to-trough drawdown, percent of trades that closed profitable, and the fill rate when the strategy assumes liquidity it didn’t have.
No network, no DOM
The strategy runs in a Web Worker with the network and the rest of the page locked out, and a 1 s timeout per bar. Bad code can’t leak data, can’t reach an exchange API, can’t hang the tab.
Strategies stay on disk
Saved strategies live in IndexedDB. They aren’t synced, mirrored, or uploaded. Export the whole workspace to a .ftm file or copy a share URL when you actually want to send it.
What it isn’t
Not a live trading bot. Not a multi-asset portfolio simulator. Not a paper-trading account with broker integration. The backtester is a strategy-research tool — when the strategy works, you act on it elsewhere.
//RUN A STRATEGY
Free.
Sandboxed.
Browser-based · local-first · no upload