chain_getBlockHash

Description

Returns the block hash for a given block number. Needed when pinning queries to historical state or verifying inclusion proofs.

Parameters

Position	Type	Description
0 (optional)	string or number	Block number (hex or decimal). Omit to get the latest block hash.

Request Example

{
  "jsonrpc": "2.0",
  "method": "chain_getBlockHash",
  "params": ["0x9fbc37"],
  "id": 1
}

Response Example

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0xae7ff263b3ca7ce2fa9c1729a4a0fd20b62d6b3befe7d9bd584afc30afc61c06"
}

Code Examples

JavaScript (polkadot.js)

const hash = await api.rpc.chain.getBlockHash(10_468_407);
console.log(hash.toHex());

Python (requests)

payload = {"jsonrpc": "2.0", "method": "chain_getBlockHash", "params": [10468407], "id": 1}
resp = requests.post(
    "https://api-astar.n.dwellir.com/YOUR_API_KEY",
    headers={"Content-Type": "application/json"},
    data=json.dumps(payload)
)
print(resp.json()["result"])