Chainlink API

Free to Use Varies (check documentation)

Overview

Chainlink is a decentralized oracle network that connects smart contracts to real-world data like price feeds, random numbers, and external APIs. It's widely used to bring off-chain data onto any EVM blockchain.

Beginner Tip

The easiest entry point is Chainlink's Data Feeds — price feed contract addresses for ETH/USD, BTC/USD, and others are published per-network so you can query them directly with a few lines of Solidity or ethers.js.

Available Data

Chainlink data via REST API

Example Response

JSON Response
{
  "status": "success",
  "data": {
    "result": "Data from Chainlink",
    "description": "Build hybrid smart contracts with Chainlink",
    "timestamp": "2025-01-15T10:00:00Z"
  }
}

Field Reference

roundId Identifier for the oracle update round; increases with each new price report.
answer The raw price value as an integer; divide by 10^decimals() to get the actual price.
startedAt Unix timestamp when this oracle round started collecting responses.
updatedAt Unix timestamp when the aggregated answer was last written on-chain; use to check data freshness.
answeredInRound Round in which the answer was computed; should equal roundId for a valid response.

Implementation Example

Request
const url = "https://chain.link/developer-resources";
const response = await fetch(url);
if (!response.ok) throw new Error(`Request failed: ${response.status}`);
const data = await response.json();
console.log(data);

What Can You Build?

Note: These code examples are AI-generated and unverified. Always refer to the official API documentation for accurate usage.

Common Errors & Troubleshooting

Wrong network contract address Using a price feed address from one network (e.g. Ethereum mainnet) on a different network (e.g. Polygon)
Always look up contract addresses for your specific network in the Chainlink Data Feeds documentation — each chain has unique addresses.
Stale or reverted answer The oracle hasn't been updated recently or the feed is deprecated
Check the 'updatedAt' timestamp from latestRoundData() and reject answers older than the feed's heartbeat interval (usually 1-24 hours).
Decimals mismatch in price calculation Price feeds return integers with a built-in decimal scale (typically 8 decimals for USD pairs)
Call decimals() on the aggregator contract and divide the raw answer by 10^decimals to get the human-readable price.

Metadata Score Breakdown

Estimated from metadata — endpoint not independently tested

This score is estimated from observable metadata — HTTPS support, authentication model, declared CORS, and documentation reachability — because the API requires authentication or exposes no publicly testable endpoint. The five-signal breakdown is only shown for live-tested APIs.

Metadata estimate · endpoint not independently tested

Technical Specifications

Auth No Auth
HTTPS REQUIRED
CORS UNKNOWN
Category Blockchain
Difficulty Beginner
Verified: 2026-04-07

Related Tags

Similar APIs

View All →