All terms
Infrastructure that makes blockchain data queryable.
Blockchains are excellent at recording data and terrible at answering questions about it. Asking a chain for every trade a wallet made last month is impractical to do directly.
Indexers read the chain, structure the data and expose it through an API so applications can query it quickly. Almost every dApp interface you use depends on one.
Block explorers, portfolio trackers and DEX interfaces all sit on top of indexing infrastructure rather than reading the chain directly.
That an indexer is a neutral pipe. It decides what data is exposed and how, it can go down, and most applications rely on one. A great deal of what looks like onchain data reaching your screen has passed through a company.
Common questions
Why is an indexer needed at all?
Does using an indexer mean trusting somebody?
Where to go next
More web3 terms
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Some of these land faster in conversation than in writing. Sessions are one to one and you can ask anything, including the things that feel too obvious to ask.