Blockchain.info — Free Bitcoin Blockchain Data API (No Key)

TL;DR

Blockchain.info offers one of the oldest and most reliable free APIs for Bitcoin blockchain data. You can query the latest block, look up individual transactions, examine address balances and history, get market price tickers, and access raw blockchain data. Basic queries require no authentication. The API has powered thousands of Bitcoin wallets, explorers, and analytics tools since Bitcoin's early days.

Quick start: https://blockchain.info/latestblock

No API key needed — just make a request!

How to Use This API

1. Latest Block

https://blockchain.info/latestblock

2. Bitcoin Ticker

Get current BTC price in multiple currencies:

https://blockchain.info/ticker

3. Address Info

https://blockchain.info/address/1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa?format=json

4. JavaScript — BTC Price Checker

fetch('https://blockchain.info/ticker')
  .then(r => r.json())
  .then(d => {
    console.log('USD:', d.USD.last, d.USD.symbol);
    console.log('EUR:', d.EUR.last, d.EUR.symbol);
    console.log('GBP:', d.GBP.last, d.GBP.symbol);
  });

5. Python — Get Block by Hash

import requests

block_hash = '000000000000000000078c89639751b1379c39b5e32d2e09b1f4e57f2a44b6a5'
resp = requests.get(f'https://blockchain.info/rawblock/{block_hash}')
block = resp.json()
print(f"Block {block['height']}: {block['n_tx']} transactions")
print(f"Size: {block['size']} bytes, Fee: {block['fee']} satoshis")

Try it: https://blockchain.info/latestblock

Try This URL Now

API Details

API URL: https://blockchain.info
Documentation: blockchain.com/explorer/api
Category: Finance
Authentication: Not Required (basic queries)
Geographic Coverage: Global — Bitcoin network

Frequently Asked Questions

Do I need an API key?: No, basic queries to blockchain.info endpoints work without authentication. Higher-rate access may require API keys from Blockchain.com.
What data can I get from the ticker?: The /ticker endpoint returns BTC prices in 30+ currencies with last, buy, sell, 15m (15-minute delayed), and symbol fields.
How do I get transaction details?: Use /rawtx/{tx_hash} to get full transaction JSON including inputs, outputs, values, and scripts.
Can I get unconfirmed transactions?: Yes, the /unconfirmed-transactions endpoint returns a JSON stream of recently broadcast but unconfirmed transactions (mempool data).
What chart data is available?: The /charts endpoint provides historical data on price, hash rate, difficulty, transaction count, Mempool size, and more.
Is there a rate limit?: Blockchain.info does not publish specific rate limits but recommends caching data and avoiding excessive polling. Heavy users should register for API access.

What You Can Build

Bitcoin price ticker widget for websites
Blockchain explorer with transaction lookup
Wallet balance checker and transaction history viewer
Mining dashboard with hash rate and difficulty charts
Payment confirmation tracker monitoring mempool