Paper Trading Research and Replay Calculation Methodology

Inspect provider evidence, next-open execution, currency rounding, pending orders and the limits of the original replay lab.

Research scope

Eight selected workflows are classified as live-market simulation, broker demo or historical replay. API support is marked only where the selected source establishes it; unknown does not mean unavailable. Account eligibility, trials and data packages remain separate from the simulator’s existence.

Input and execution rules

Provide 2–5,000 increasing daily rows, strict UTF-8 CSV up to 2 MB, with Date, Open, High, Low, Close and optional integer Volume. Prices must be positive, at most four decimals, and consistent with the high-low range. No sorting, deduplication, missing-row filling or external calendar validation is performed. Initial cash and fixed fees use currency cents. Runs exceeding the supported exact integer currency range are rejected; reset with smaller units or a shorter history.

One pending next-open order

Queue a whole-unit BUY while flat or SELL of the complete existing position. Advance to the next supplied row to attempt the fill; cancel before advancing to remove it. Only one request may be pending. Insufficient cash after the full notional and fee rejects the request, with no partial fill or charge. SELL that would leave negative cash is also rejected and leaves the position open.

Costs, marking and accounting

Adverse basis-point impact increases buys and reduces sells; adjusted price rounds half-up to four decimals, then notional and proportional commission round to cents. Fixed fee applies only on fills. Constant impact can put the price outside a bar range. Marks use the revealed close; unrealized P&L includes entered opening fee but no hypothetical exit fee. Realized plus unrealized equals total equity change.

Session and model boundaries

Initial cash is the drawdown baseline; close-equity highs determine currency drawdown, not intraday peaks. The end does not liquidate holdings. JSON contains source CSV, options and action log, up to 8 MB; restore recalculates results. Up to 10,000 actions. No automatic saving, real broker calls, dividends, corporate actions, FX, shorting, leverage, partial exits, options lifecycle, futures settlement, stop/limit orders or volume-constrained fills.