I'm a pretty heavy user of trading sim, and there only seems to be a bit of scattered info on it in the forums so I thought I'd post a detailed thread here along with some recent improvements they've done.
For those who don't know, TradingSim (www.tradingsim.com) is a dedicated replay paper trading platform that runs in the browser. One can choose any date, setup a watchlist and playback stock data. There are buttons for play, pause, step to next candle, speed up, slow down etc. You can set your account size, buy, sell, short, limit and stop orders are all there.
The advantages of using such a platform:
Trade outside of market hours
Drastically increase the amount of practice trading for a given time of day (for instance the open)
Trade in different market conditions
Use it as a research tool to study historical data, refine patterns and strategies, etc.
One of the main drawbacks that people have commented here on the forums here is that it does not have pre-market and post market. They have since added this a little while ago. I'd say the only key thing that's still missing is level 2, although they do have order flow; and that also shows the current spread.
There is obviously no premarket gapper scanner or anything like that. For trading practice I simply look up the respective recap from Andrew on youtube in order to get a watchlist.
I spent quite some effort getting this das-like, and I'm relatively happy with the result. Take a look for yourself, and note that my DAS setup is slightly different than Andrews (I use green candles, different thickness MAs). Like DAS, there are a lot of options, it takes a little while to find everything you need. One rather critical option that vastly improved it for me was the 'Scale series only' under the 'Scale' of the chart settings. This stops the chart zooming out to fit the 50 and 200 SMA when they are out of screen. Just like DAS you can mark your charts with relevant levels from the premaket or daily, levels can be moved across charts via one by one via a copy-paste type functionality, but given the amount of clicking involved it's just as fast to draw them again.
Some of the drawbacks the platform still has:
Calculation of the VWAP in the pre-market is incorrect (I am currently in contact with them about this)
No level 2
Hotkey functionality is a bit weak compared to DAS
For active trades, it shows your average price on the chart, as well as relevant limit/stop orders, which is pretty cool, however once a trade is closed, there are no triangles to show you your orders. This makes it difficult for reviewing trades. This also facilitates overtrading or scaling out too quickly in my mind as you can't see the array of triangles you are leaving behind.
During my usage of the platform I have found some bugs or oddities and sent them feedback. They have been fairly responsive about addressing all the feedback I have sent them, and a number of things have been fixed thus far.
A word to pricing and competition. I tried both NinjaTrader and ThinkorSwin in the beginning, both of which are free. Ninja trader didn't work at all, replay only seemed to work for futures and forex. ThinkorSwim is also free but requires an ameritrade TD account. Based on feedback I heard from others from the community that it was rather clunky and not really usable, I didn't bother trying it out. TradingSim is $300 a year, and they offer a 10 day trial. Compared to the cost of DAS I personally think this is totally reasonable, particularly for people with jobs, or in other time zones who need to practice out of market hours.
To conclude I want to emphasize that whilst I am happy with using this software, it is clearly no replacement for the DAS trader simulator with real time data and participating in the chat. Personally, I find I take tradingsim less seriously than the DAS sim, something about the fact the things are not happening real time really takes the pressure off. Therefore it is essential to participate in the market daily to practice in realtime market conditions, and on the platform you will go live with.
I'd be interested to here from other members using tradingsim and what they think. Anything to add or any questions?