Market Replay is the ability to record market data and replay it at another time. It is the same idea as recording your favorite TV show during the day and watching it at some other more convenient time. Unlike most products that only allow you to replay one market at a time, NinjaTrader provides synchronous replay of any and all recorded markets and delivers this market data to all NinjaTrader windows as if it was happening in real-time. Therefore, you can have multiple SuperDOMs and charts replaying different markets all at the same time. You can trade in simulation against this data at varying levels of replay speed.
NOTE: Market Replay is not supported in the NinjaTrader Direct Edition.