Blockchain technology has revolutionized how we handle data and transactions. As a developer, accessing reliable Blockchain APIs is essential for building decentralized applications (dApps), wallets, and analytics tools. This guide covers Blockchain Data APIs, their endpoints, parameters, and response formats to help you integrate blockchain functionalities seamlessly.
Blockchain Data API Overview
Blockchain APIs provide programmatic access to blockchain data, including blocks, transactions, addresses, and charts. Many endpoints support CORS headers—simply append &cors=true to your GET request for cross-origin compatibility.
Core Features
✔ Real-time blockchain data retrieval
✔ Support for raw, JSON, and hex-encoded formats
✔ Multi-address queries & balance checks
✔ Unconfirmed transaction monitoring
Key API Endpoints
1. Single Block
Endpoint:
https://blockchain.info/rawblock/$block_hash Parameters:
?format=hex– Returns block in hex-encoded binary.
Example Response:
{
"hash": "0000000000000bae09a7a393a8acded75aa67e46cb81f7acaa5ad94f9eacd103",
"height": 154595,
"tx": ["--Array of Transactions--"]
} 2. Single Transaction
Endpoint:
https://blockchain.info/rawtx/$tx_hash Parameters:
?format=hex– Retrieves transaction in hex format.
Example Response:
{
"hash": "b6f6991d03df0e2e04dafffcd6bc418aac66049e2cd74b80f14ac86db1e3f0da",
"block_height": 12200,
"inputs": [{"prev_out": {"value": "100000000"}}]
} 3. Chart Data
Endpoint:
https://blockchain.info/charts/$chart-type?format=json Example Response:
{
"values": [{"x": 1290602498, "y": 1309696.2116000003}]
} 4. Block Height
Endpoint:
https://blockchain.info/block-height/$block_height?format=json Response:
{
"blocks": ["--Array Of Blocks--"]
} 5. Address Lookup
Single Address
Endpoint:
https://blockchain.info/rawaddr/$bitcoin_address Parameters:
&limit=50– Limits transactions displayed.&offset=100– Paginates results.
Example Response:
{
"address": "1AJbsFZ64EpEfS5UAjAfcUG8pH8Jn3rn1F",
"final_balance": 100100000
} Multi-Address
Endpoint:
https://blockchain.info/multiaddr?active=$address|$address Parameters:
&n=50– Adjusts transaction limit.
Response:
{
"addresses": [{"total_received": 1401000000}],
"txs": ["--Latest 50 Transactions--"]
} FAQs
Q1: How do I fetch unspent transaction outputs (UTXOs)?
A: Use:
https://blockchain.info/unspent?active=$address Optional: &confirmations=6 filters by minimum confirmations.
Q2: Can I monitor unconfirmed transactions?
A: Yes:
https://blockchain.info/unconfirmed-transactions?format=json Q3: What’s the maximum transaction limit per address query?
A: 50 for single-address, 100 for multi-address.
Q4: How do I check balances for multiple addresses?
A: Use:
https://blockchain.info/balance?active=$address|$address Conclusion
Blockchain APIs empower developers to build scalable, secure applications. Whether you’re analyzing chart data, tracking UTXOs, or querying multi-address transactions, these endpoints offer robust solutions.
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By leveraging these APIs, you can streamline development and focus on creating innovative blockchain solutions.