Chainlink (LINK) is a decentralized oracle network which aims to connect smart contracts with data from the real world. Chainlink was developed by Sergey Nazarov, with Steve Ellis as the other co-founder. It held an ICO in September 2017, raising $32 million, with a total supply of 1 billion LINK tokens. LINK, the cryptocurrency native to the Chainlink decentralized oracle network, is used to pay node operators. Since the Chainlink network has a reputation system, node providers that have a large amount of LINK can be rewarded with larger contracts, while a failure to deliver accurate information results in a deduction of tokens. Developers describe LINK as “an ERC20 token, with the additional ERC223 'transfer and call' functionality of transfer (address, uint256, bytes), allowing tokens to be received and processed by contracts within a single transaction.” Following the 2017 $32 million LINK ICO, 32 percent of LINK tokens were sent to node operators to incentivize the ecosystem and 30 percent stayed within Chainlink for development (35 percent were sold in the public token sale).

https://chain.link/