Chainlink

Chainlink Data Feeds are pre-published onchain data products. A protocol reads a selected feed proxy for a stated asset, network and data type instead of submitting a fresh request whenever it needs a value; the exact feed specification is therefore the relevant integration boundary.

Oracle operators aggregate a feed-specific answer

For a standard market-price feed, multiple oracle operators query data providers, submit observations during an aggregation round, and the aggregator validates and combines those observations into an onchain answer. The response threshold, sources and methodology are feed-specific, and some catalogued feeds use other models such as proof of reserve, exchange rates, technical metrics or custom indices.

A consumer normally calls the feed proxy through its published interface to obtain the latest answer and metadata. The proxy can continue to point to a replacement aggregator after an upgrade, which is why an integration should use the specified proxy rather than hard-code an underlying aggregator.

Updates are triggered, not continuously streamed

A new round begins when an observed offchain value crosses the configured deviation threshold or when the heartbeat interval elapses, whichever happens first. The visible value is the most recently confirmed answer and timestamp; a quiet market can therefore leave a valid answer unchanged until its heartbeat, while chain conditions can delay a triggered update reaching the chain.

The feed is a read integration rather than a per-query bonded request. Feed operations are funded at the feed level, but a protocol still pays the gas for its own state-changing action when it reads and acts on an answer.

Freshness controls distinguish it from UMA assertions

An integrating protocol should confirm the feed address and interface for its chain, inspect the updated timestamp against its own freshness limit, and define range checks, fallbacks or pause behavior. A valid answer does not supply the application’s collateral policy, authorization logic or circuit breakers, and thin liquidity or unusual market events can still make a feed unsuitable for a particular action.

UMA is the close contrast when the required result is an application-defined, discrete claim that can be challenged. Chainlink is designed for repeatedly reading an available numeric feed with feed-specific deviation and heartbeat behavior; UMA instead introduces claim wording, bonds, liveness and a dispute path before settlement.