Paper trading lets you run a strategy against real, live prices using fake money. It is the flight simulator of trading: you make the same decisions, see the same fills, and track the same P&L — without the consequences of a real loss while you are still learning.
Its biggest value is behavioural. Most strategies fail not because the signal is wrong but because the trader abandons it under stress. Paper trading reveals whether you can actually follow a system through a drawdown before real money is on the line.
The honest caveat: paper trading removes the emotional weight of real risk, so live results are usually a little worse. Use it to validate process and mechanics, then size up slowly with real capital.
Sintinel includes a paper-trading sandbox wired to live signals, so you can test how the composite score and Kelly sizing would have performed on your own watchlist before committing capital.