Indexer & Explorer

Indexer

Indexing protocols organize information in a way that applications can access it more efficiently. For example, Google indexes the entire internet to provide information rapidly when you search for something.

The Graph is a decentralized and open-source indexing protocol for querying networks like Ethereum. In short, it provides a way to efficiently store data emitted by events from smart contracts so that other projects or dApps can access it easily.

Furthermore, developers can build APIs, called Subgraphs. Users or other developers can use Subgraphs to query data specific to a set of smart contracts. Data is fetched with a standard GraphQL API. You can visit their documentation to read more about The Graph protocol.

Explorer

Block explorers can be thought of as search engines for the blockchain. They allow users to search information such as balances, contracts, and transactions. More advanced block explorers even offer indexing capabilities, which enable them to provide a complete set of information, such as ERC20 tokens in the network. They might even offer API services to access it via external services.