chain_subscribeNewHeads

Description

Streams every new block header as soon as it is produced. Ideal for dashboards, mempool monitors, and latency-sensitive services.

Parameters

This method does not require parameters.

WebSocket Request

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

Notification Example

{
  "jsonrpc": "2.0",
  "method": "chain_subscribeNewHeads",
  "params": {
    "subscription": 1,
    "result": {
      "number": "0x9fbc37",
      "hash": "0xae7ff263b3ca7ce2fa9c1729a4a0fd20b62d6b3befe7d9bd584afc30afc61c06",
      "parentHash": "0x68afcd0090cb8fd89d37729aaf6aa600ff8ebaaad308ed02427d0e229b417d23",
      "stateRoot": "0xacc622cdb3d892f7688f6e9887b469ddf843ece0012dacff41456637d26e66f8",
      "digest": { "logs": [
        "0x066175726120259b7a1100000000",
        "0x045250535290e2ffc2b224d51b3406cab1e3491df1a37b2a25ddcab9496f5fffb4ba1a02834dd218af06"
      ] }
    }
  }
}

JavaScript Example

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

api.rpc.chain.subscribeNewHeads((header) => {
  console.log(`New head #${header.number} -> ${header.hash.toHex()}`);
});