Quantopian was an online platform that enabled users to create, test, and refine algorithmic trading strategies. The platform offered a collaborative environment for quantitative finance enthusiasts to develop their own trading algorithms using Python, alongside access to free financial data and a backtesting engine to simulate trading strategies. Quantopian also hosted competitions and allowed selected strategies to be funded, with potential profit-sharing opportunities for creators. As of 2020, Quantopian ceased operations and its community resources were no longer available.