A price oracle supplies a contract with a reference value that the contract cannot simply infer from its own code. The reference may describe an exchange rate, an index, or another market measurement. A feed's usefulness depends on how observations are gathered, aggregated, updated, and delivered. The returned number also has units, precision, and a timestamp or comparable freshness information. Treating it as an unqualified universal market price discards the assumptions that make it meaningful.

Suppose a lending application values collateral using a feed with eight decimal places. An answer of 250,000,000 represents 2.5 units of the quoted currency, not 250 million units. The application must also confirm the intended pair and decide how old an observation may be for its use case. A feed for token-to-ETH and a feed for token-to-USD are not interchangeable without another conversion. Incorrect scaling or pair selection can distort collateral calculations even when the reported answer itself is authentic.

An oracle can deliver a correctly authenticated observation that is unsuitable because the underlying market is thin, the update is stale, or a component network is unavailable. A current automated-market-maker reserve ratio can also be moved by trades and should not automatically be treated as a manipulation-resistant oracle. Applications need explicit handling for missing or unacceptable observations, with trade-offs between stopping actions and accepting weaker information.

Review the feed's methodology and the consuming contract's validation together; neither the oracle brand nor a recent transaction timestamp alone proves a safe valuation.