Datality is the first blockchain-based data marketplace directly connecting buyers and sellers to safely transact data for value in a free market. Existing one-sided marketplaces dominate supply and market share – they hold back private sellers of data, inflate the cost to data consumers, and restrict a l the economic advantages of a free market. Datality solves the multilateral data marketplace challenges of trust, provenance, fraud risk, appropriability and market thickness by employing blockchain, escrow systems, covenants, reputation management and local network effects.