M
API Matrix

Chainlink API

Blockchain / No Auth Required Beginner HTTPS
Free to Use Varies (check documentation)
87 Score
Grade A
Visit Official Site Compare Alternatives

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
JSON-formatted response data
Freely accessible without authentication

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 

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.

Matrix Score Breakdown

🌐 Reachability 30/30
⚡ Speed 20/20
🔒 Security 15/15
🛠 Developer XP 15/20
✓ Reliability 7/15
Response Time 134ms

Fully tested on Apr 5, 2026

Technical Specifications

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

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