ETFreplay is a web-based platform that provides tools and analytics for exchange-traded fund (ETF) investors and traders. The website, http://etfreplay.com, offers features such as backtesting capabilities, relative strength analysis, and performance comparison tools. Users can create and test customized ETF portfolios, analyze historical performance data, and gain insights into market trends. The platform is designed to assist both individual and professional investors in making informed decisions by providing comprehensive data and analytical tools tailored to ETFs.