blockchain – How to get price information from Chainlink?
With Chainlink price feeds, each data feed is updated by a decentralized oracle network. Each oracle in the set publishes data during an aggregation round. That data is validated and aggregated by a smart contract, which forms the feeds latest and trusted answer.
Each oracle operator is rewarded for publishing data. On mainnet, sponsors are paying the LINK associated to keep those feeds live, decentralized, and secure, so they are not free. This allows the network to be a shared resource where everyone chips in a tiny bit and makes them even cheaper than running even your own centralized feed.
That being said, the price feeds are currently a simple
view function, and anyone can technically use them as access controls are on the roadmap to be built at some point. It’s not really economical or fair for those backers who are paying to support them for everyone else. Until access controls are built, please reach out if you are using them on mainnet and learn how you can contribute to keep them reliable honest, and secure.
With API calls, Chainlink enables your contracts to access any external data source, through their decentralized oracle network. Making a HTTP GET request will fail unless your deployed contract has enough LINK to pay for it, therefore one needs to fund that smart contract.
If your contract is calling a public API endpoint, an Oracle job may already exist for it. To check available jobs and GET request prices, visit https://market.link/