I do consulting for financial service firms (brokers, banks, ISVs) and have a brokerage client who's interested in understanding the scope & scale of implementing a paper trading system allowing their customers to learn how to use their front-end. I could suggest a simple database solution, but hoped to understand the scope of a larger project . . like replicating their production system with simulated trading (and/or data) or also support a development environment for vendors to write to their API (a larger scope effort, and greater cost/ben). I am familiar with server-side paper trading systems available through IB, optionsXpress and MBT, as well as client-side ones like patsystems and TT had/have . . but in those cases, I was on the other side, managing developers who integrated our front-end to the brokers' trading, quotes and account information via their API (ie, I just needed access to APIs supporting simulated order entry, account information, data feeds, etc.). Also, on those projects, some brokers had paper trading that their customers used to experience the front-end's functionality, but that couldn't be used to develop to their API. I haven't been able to find any resources or experiences that firms have had implementing a paper trading service - especially things like best practices, things to consider during scope & design (like supporting both customers and developers, adding new asset classes/vendors), etc.. So . . any insight would be much appreciated! Brent