chain_getHeader

Returns the block header for a given hash on Bittensor.

Use Cases

• Lightweight queries - Get header without full block data
• Chain synchronization - Track block production for decentralized AI inference, subnet-specific AI models, TAO staking, and cross-subnet AI collaboration
• Parent chain navigation - Follow parentHash links

Parameters

Parameter	Type	Required	Description
blockHash	String	No	Block hash. If omitted, returns latest header

Request

{
  "jsonrpc": "2.0",
  "method": "chain_getHeader",
  "params": ["0x2f0555cc76fc2840a25a6f3a0f0e6d0b1a6dd2e0cecc9e4c2e9e6f3a8d2e5c1b"],
  "id": 1
}

Code Examples

cURL

curl https://api-bittensor-mainnet.n.dwellir.com/YOUR_API_KEY \
  -X POST \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "chain_getHeader",
    "params": [],
    "id": 1
  }'

JavaScript

import { ApiPromise, WsProvider } from '@polkadot/api';

const provider = new WsProvider('wss://api-bittensor-mainnet.n.dwellir.com/YOUR_API_KEY');
const api = await ApiPromise.create({ provider });

// Get latest header
const header = await api.rpc.chain.getHeader();
console.log('Block number:', header.number.toNumber());
console.log('Parent hash:', header.parentHash.toHex());

await api.disconnect();

Python

import requests

def get_header(block_hash=None):
    url = 'https://api-bittensor-mainnet.n.dwellir.com/YOUR_API_KEY'
    params = [block_hash] if block_hash else []

    payload = {
        'jsonrpc': '2.0',
        'method': 'chain_getHeader',
        'params': params,
        'id': 1
    }

    response = requests.post(url, json=payload)
    return response.json()['result']

header = get_header()
print(f"Block number: {int(header['number'], 16)}")

Related Methods

• chain_getBlock - Get full block with extrinsics
• chain_getBlockHash - Get block hash by number