MarketStore is an open-source database server optimized for financial timeseries data, designed in pure Go to address scalability issues with large amounts of market data used in algorithmic trading backtesting, charting, and analyzing price history. The problem it solves is the performance bottleneck of accessing historical price data for thousands of symbols, which was handled using HDF5 files but required a more efficient solution. MarketStore aims to provide an extensible DataFrame service accessible from anywhere in the system, with features such as HTTP-based API, MessagePack binary serialization, time-indexed row orientation storage format, utilizing filesystem holes, and custom plugins to support different asset classes and markets. The database server is designed with a true database architecture, utilizing a plugin system for data ingestion, and has native Go and Python clients that perform well. MarketStore is available today as an open source project on GitHub and is production ready, aiming to help individuals have more technology power in the financial markets by providing technology in this way.