chainlink

Call latestRoundData() on the AggregatorV3Interface feed contract, then validate that answer is positive, updatedAt is within the feed's heartbeat threshold, and answeredInRound is not less than roundId. Always call decimals() rather than assuming 8 decimals.

Extend VRFConsumerBaseV2Plus and call requestRandomWords with a RandomWordsRequest struct containing keyHash, subId, requestConfirmations, callbackGasLimit, and numWords. Fund a subscription with LINK or native token and register your contract as a consumer.

Chainlink offers zero-cost reads, 1000+ EVM feeds, and the VRF/CCIP/Automation ecosystem. Pyth provides sub-second price freshness, confidence intervals, and non-EVM chain support, but consumers pay gas to push price updates on-chain.

Unfulfilled VRF requests usually mean an underfunded subscription, an unregistered consumer contract, or a wrong keyHash for your chain. Check the subscription balance via getSubscription, verify consumer registration, and confirm the gas lane keyHash matches your network.

Yes, on Arbitrum, Base, and Optimism you must check the sequencer uptime feed before trusting price data. When the sequencer restarts, oracle updates lag, so enforce a grace period after it comes back online before accepting prices.

Stuck CCIP messages typically result from the receiver's _ccipReceive reverting, an insufficient gasLimit in extraArgs, or the sender not being allowlisted on the destination contract. Look up the message ID on ccip.chain.link and use manual execution to retry.