The Graph is an Ethereum-based indexing protocol that allows developers to easily access data from blockchain networks like Ethereum and IPFS to run their decentralized applications efficiently. Popular dApps like Aave, Curve and Uniswap use The Graph.
The Graph analyzes blockchain data and stores it into open APIs called Subgraphs. DApps can easily query these subgraphs using the popular query language, GraphQL, to retrieve relevant data immediately.
There are four contributors to The Graph's ecosystem – developers, curators, indexers and delegators. Developers create and use subgraphs in dApps; curators identify which subgraphs are valuable to the network and can be indexed; indexers are The Graph's node operators who fulfill user queries; delegators support the network by delegating GRT to indexers.
To become a curator, indexer or delegator and earn fees for your services, you need to stake GRT tokens. If you are a dApp developer, you can buy GRT and use it to obtain valuable data from The Graph.