Subgraphs
The Graph is a protocol for building decentralized applications on Ethereum and IPFS using GraphQL. The protocol enables developers to browse through APIs, referred to as subgraphs, and query blockchain data quickly.
The Graph includes a Graph Node, which is an application that processes the entire blockchain and allows subgraphs to be registered on it. These subgraphs define what contracts to listen to and how to process the data when events are triggered on the contracts
Purpose
Understanding and Aggregating Data
https://coinmarketcap.com/alexandria/article/a-deep-dive-into-the-graph