You can use NinjaTrader (even the free Simulation Edition) with TradeStation's real-time data feed.
NOTE: The TradeStation connection does NOT support symbols that represent continuous contracts. Market data will only stream for individual contracts.
Initial Set Up
1. NinjaTrader must be installed
2. Start TradeStation
3. Select the menu File-->Import/Export EasyLanguage
4. Select "Import EasyLanguage file (ELD, ELS or ELA)"
5. Click "Next"
6. Select the file <NinjaTrader Installation Folder>\bin\AutoTrade\NINJATRADER.ELD"
7. Click "Next"
8. Click "Next"
9. Click "Finish" and confirm any upcoming query box by clicking "OK"
Connecting
1. Start NinjaTrader and connect to the "External Data Feed Connection" via the Control Center window, File-->Connect menu
2. Start TradeStation
3. Within TradeSation, open a chart window (MSFT for example) and via the right mouse click context menu, select "Insert Strategy..."
4. From the dialog window "Insert Strategies" select "NTExternalFeed" strategy and press the "OK" button
5. A new window will appear "Format Analysis Techniques & Strategies", press the "CLOSE" button
6. Within NinjaTrader, select MSFT from any of the order entry or chart window
You will now receive real-time data from TradeStation in NinjaTrader.
Symbol Mapping
Please see the "TradeStation Symbol Mapping" section.
* Only level one data will be transmitted. Market depth is not supported.