I'm looking for a good platform and/or data feed to do real-time analysis of market depth data across a broad number of securities, in order to generate custom signals. As a starting point, Nasdaq TotalView could be utilized for data. I have a software development background, but am still fairly new to the trading tools ecosystem. I typically code in C#, but can do other languages if needed. Would appreciate any insights anyone here may have on this. So far I've looked at TradeStation, Interactive Broker, Bookmap, dxFeed, etc.