chain_getHeader

Retrieves the header for the best block or for a specific block hash. The header exposes parent linkage, state and extrinsic roots, and consensus digest logs needed for block verification.

Parameters

Parameter	Type	Required	Description
hash	string	No	Hex-encoded block hash. When omitted, the header of the best block is returned.

Returns

Field	Type	Description
result	object	Header object containing parentHash, number, stateRoot, extrinsicsRoot, and digest.logs.

Request Example (Latest Header)

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

Response Snapshot

{
  "jsonrpc": "2.0",
  "result": {
    "parentHash": "0xbec4859ed2032e0e046e7a78a3882c5ae8b7d51d16a083635d5b5ad309b30d12",
    "number": "0x62726a",
    "stateRoot": "0x84351d19940a55e597b6d8b95176bf0c900935fb7e268bad21c0ba1e91ea9eca",
    "extrinsicsRoot": "0x6db96b60e428cd53e0453209ca50b5de7d592a18adfd4819c7ccb9afee0ab300",
    "digest": {
      "logs": [
        "0x066e6d62738018fedf34063e6bf1cce87512dfbffdd560f2f45a0910b9e77f157b6b16ee1f4c",
        "0x045250535290c08152936b6cc68ce4b7b680a3a5b5f45027688a33011b41c015b20b4b08999aaa49ae06"
      ]
    }
  },
  "id": 1
}

Code Example (@polkadot/api)

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

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

const header = await api.rpc.chain.getHeader();
console.log('Best block number', header.number.toNumber());
console.log('Parent hash', header.parentHash.toHex());

Usage Notes

• Digest entries include consensus messages such as Nimbus authoring slots and GRANDPA justifications.
• Supply a finalized hash from chain_getFinalizedHead to ensure the header cannot be re-orged away.
• For full block contents, follow up with chain_getBlock.

Related Methods

• chain_getBlockHash
• chain_getBlock
• chain_subscribeNewHeads