Think the main difference is how the data is handled. Never used ninja much but I would assume that with ninja, the data is stored client side.
ToS, tradestation, I’m guessing but most likely the data is all server side. So if you request a scan across all stocks for new highs, their computing on their end and sending the data back to you of results.
Ninja isn’t a data vendor, they support data feeds. Their limited by the data feed. So say IQFeed has a 500 symbol limit, and your running a scan, your limited by that 500 symbol limit.
Now say the benefit of having ninja is you could simultaneous monitor 500 symbols on tick data while I’m assuming that’s just not going to happen on TOS. Their not sending that much data out. It’s easier to just compute on their end and send results back, less bandwidth.
I use Amibroker for instance and I love how fast I can go through charts. Data is stored in my end and if I perform a scan over the data and it’s loaded to my ram, flipping through charts is instantaneous while using some software like TOS or tradingview, your requesting charts for every new symbol.