Mempool API
Overview
Mempool.space is a Bitcoin blockchain explorer API that focuses on real-time transaction fee estimation and mempool (pending transaction pool) analytics. It provides recommended fee rates in sat/vByte so developers can help users set appropriate transaction fees for timely confirmation. No API key or authentication is needed, making it one of the most accessible Bitcoin APIs for beginners.
Beginner Tip
Use the /api/v1/fees/recommended endpoint to instantly get the current Bitcoin fee recommendation — no sign-up required, just call the URL and use the "fastestFee" value to set an appropriate fee for urgent transactions.
Available Data
Example Response
{
"id": "bitcoin",
"symbol": "btc",
"current_price": 65432.1,
"market_cap": 1280000000000,
"price_change_24h": 1250.5,
"price_change_percentage_24h": 1.95,
"total_volume": 28500000000
} Field Reference
fastestFee Recommended fee in sat/vByte to get confirmed in the next block (~10 minutes). halfHourFee Fee rate in sat/vByte for confirmation within approximately 30 minutes. hourFee Fee rate in sat/vByte for confirmation within approximately 1 hour. economyFee Lower-priority fee rate in sat/vByte; confirmation may take several hours. minimumFee Minimum fee rate accepted by the network; transactions below this are likely rejected. Implementation Example
// ⚠️ Note: This URL may be a documentation page. Check official docs for actual API endpoint.
const url = "https://mempool.space/api";
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
Matrix Score Breakdown
Fully tested on Apr 5, 2026
Technical Specifications
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