The Graph is the indexing and query layer of the decentralized web. Developers build and publish open APIs, called subgraphs, that applications can query using GraphQL. There is a hosted service in production that makes it easy for developers to get started building on The Graph, and the decentralized network will launch later this year.
The Graph currently supports indexing data from Ethereum, POA, and IPFS, with more networks coming soon. To date, ~1,700 subgraphs have been deployed for dApps like Aragon, Uniswap, Synthetix, Balancer, Gnosis, Balancer, Livepeer, and Decentraland.