Decentralized finance — defi — is not a single product or platform. It is a collection of financial goods and services that operate through automated software programs called smart contracts, running on public blockchains, accessible in principle to anyone with the requisite technical knowledge and some quantity of cryptocurrency. The Congressional Research Service, in an April 2026 overview of the sector, defines it as a system characterized by “highly automated financial networks that have no single point of failure, do not rely on a single source of information, and are not governed by a central authority.”