QuantConnect - QuantConnect provides a free algorithm backtesting tool and financial data so engineers can design algorithmic trading strategies. We are democratizing algorithm trading technology to empower investors.
JStock - JStock makes it easy to track your stock investment.
quantra - A public API for quantitative finance made with Quantlib
PTMC - PTMC | Protrader Multi-Connect is designed for both professional and retail day traders or...
Quantopian - Your algorithmic investing platform
ProRealTime - Online trading, charting and technical analysis of stocks, futures, forex and commodities.