1. Eth and smartcontracts. We all know smartcontracts are revolutoinary, but their use cases are limited. Smartcontracts are awesome, but they are confined within the blockchain and data on the blockchain. In otherwords, right now smartcontracts are “you send 1 eth and I’ll send back 1000 McTokens”, and this contract is verifiable/trustless/amazing but its stuck within the universe of Ethereum and the data Ethereum understands

2. It is possible to use external data to inform these contracts, but right now that process is centralized. This is a problem. Lets say the external data is a transaction of Dollars for ETH. So you send 300$ to bank account X, and then I send one Eth to your address. Right now you either do that through a third party (CoinBase), OTC (LocalBitcoins) or whatever else centrlized system you want to use.

Knocking out that centralization, where you have to trust someone, is THE key to SmartContracts having a real world use case. But how do you get that information — the fact that the $300 has been sent — onto the blockchain using data that the smartcontract understands?

1. Oracles. Right now the answer is “hey we can hire Oracle X to do the translation to represent this bank dollar transaction on the blockchain.” The “oracle problem” with this is that you are 100% TRUSTING that oracle to act prudently. That they don’t tamper with the data. So we can kill coinbase but now we have to trust the oracle instead of coinbase .This is a HUGE problem for Banks who want to get into blockchain but have to trust a centralized oracle to translate data. This Oracle can be hacked, falsified or defrauded.

2. ChainLink - this service DECENTRALIZES that translation process of the Oracle. Now, the translation is trustless, and you have a trustless data feed that informs the trustless smart contract.

Multibillion dollar institutions can rely on distributed blockchain technology and know the data that informs their smart contracts is tamperproof.

So Thats what ChainLink does. ChainLink is the first decentralized Oracle that allows anyone to securely provide smart contracts with access to external data, off-chain payments, and really literally any other API you can dream up. Confirmation of delivery of an items (RFID, like Walton), confirmation of a wire being sent or received, interest rates from any central bank, sports scores, product/machine uptime, price of Eth/BTC in real time, weather patterns etc. Right now smart contracts are simple if/then functions where you go and manually do the if so the then comes back. Now with Oracles smartcontracts can automatically confirm or deny if then statements without any human interaction. Transactional automation for agreed upon terms on steroids.

Anyone can now engrain off-chain data directly onto the blockchain in an actually decentralized way and use that data to directly inform trustless smart contracts, and since the Oracle is decentralized you know the data feed is secure and you’re not concerned with tampering on the Oracle’s part. This is like a skeleton key to actualize the data on the blockchain and apply that data to real world use cases.