Tradebreath is a trading strategy backtesting agent that supports multiple asset classes including forex, stocks, crypto, indices, commodities, ETFs, and bonds. The platform offers two primary modes of operation: manual tick-by-tick replay on a chart and an AI agent that generates and executes strategies from natural language descriptions. Data sources include tick history with L1 bid and ask data, as well as uploaded OHLCV or tick CSV files that are parsed directly in the browser. The AI agent can write strategies or custom indicators based on plain language rules, run the backtest, and explain the actions it took. Users can take over on the chart while the replay runs, adding entries or closing early. The platform includes 36 built-in indicators and allows for the creation of custom indicators. Strategies are saved with a version control system that creates a tree structure, enabling users to fork any version to test different parameters without overwriting previous work. Strategies and indicators can be exported as scripts. The typical workflow involves the AI running a session, orders populating a list, and the user taking over on the chart. Each session concludes with a report that includes trade statistics, a performance calendar, a Monte Carlo simulation, and an AI analysis of the results. Reported metrics include profit factor, max drawdown, and Sharpe ratio. The service is free to start.