What is Subgraph (The Graph)?

A subgraph is a specialized type of application programming interface (API) employed by The Graph indexing and querying platform. It is designed to create a global graph — via the Ethereum network — of some of the world's most important public data, allowing software developers to use, index, and serve blockchain data in a cryptographically verifiable manner. Subgraphs help reduce the typically centralized structure of mainstream indexing servers, which often require significant engineering and hardware resources to achieve reasonably secure access to decentralized data.