What is Chainlink (LINK)?

Chainlink is a network that brings outside information onto blockchains. A smart contract cannot look up the price of ether or the result of a payment by itself. Chainlink supplies that data. LINK is the token used to pay for it.

Where it came from

Sergey Nazarov and Steve Ellis founded Chainlink in September 2017, when its whitepaper was published. The network went live on Ethereum in May 2019.

How it works

Lesson 7 explains smart contracts: programs on a blockchain that run exactly as written. They can only see what is already on the chain. A service that brings outside data in is called an oracle.

Chainlink runs many independent computers, called nodes, that fetch the same data, such as the price of ether in dollars, and combine their answers. A lending app (Lesson 43) can then use that price to decide when a loan is under-collateralised.

Chainlink also offers a service called CCIP for sending tokens and messages between blockchains. Lesson 33 explains why moving value between networks is risky.

Supply and the LINK token

• The total supply is capped at 1 billion LINK. All of it already exists. It is a token on Ethereum, also available on other networks.
• Many tokens are held outside circulation and released over time. Since 2022, a reserve has sent tokens to the market in scheduled quarterly releases. One in June 2025 moved about 17.9 million LINK, mostly to Binance.
• LINK pays node operators for their work. Holders can also stake it: in late 2023 the staking pool opened to 45 million LINK, with a 28-day wait to withdraw.
• In August 2025, Chainlink started a reserve that converts some of its revenue into LINK and holds it. It said it did not expect to withdraw from it for several years.

What people use it for

Lending apps, exchanges and other DeFi services use Chainlink price feeds. People buy LINK to hold, trade or stake.

Risks to know

• A single point many apps depend on. If a price feed were wrong or late, the apps that rely on it could liquidate loans at the wrong price. Lesson 45 covers risks like this.
• New supply. Scheduled releases from the reserve add tokens to the market.
• Staking is not free money. Lesson 50 explains how to judge a staking offer. Community stakers could not be slashed when the 2023 pool opened, but the rules can change.
• Price swings. Like most tokens, LINK can fall far and fast.

Learn more

Lesson 7 covers smart contracts, Lesson 41 introduces DeFi, and Lesson 9 explains the difference between a coin and a token.