get_tip_header - Nervos

Example code for the get_tip_header JSON-RPC method. Complete guide on how to use get_tip_header JSON-RPC in GetBlock Web3 documentation.

Returns the header of the tip block in the canonical chain. This is the cheapest way to check the current chain tip and confirm node liveness.

Parameters

• None

Request Example

cURL

curl --location --request POST 'https://go.getblock.io/<ACCESS-TOKEN>/' \
--header 'Content-Type: application/json' \
--data-raw '{
    "jsonrpc": "2.0",
    "method": "get_tip_header",
    "params": [],
    "id": "getblock.io"
}'

JavaScript (Axios)

import axios from 'axios';

const data = JSON.stringify({
    "jsonrpc": "2.0",
    "method": "get_tip_header",
    "params": [],
    "id": "getblock.io"
});

const config = {
    method: 'post',
    url: 'https://go.getblock.io/<ACCESS-TOKEN>/',
    headers: {
        'Content-Type': 'application/json'
    },
    data: data
};

axios(config)
    .then(response => console.log(JSON.stringify(response.data, null, 2)))
    .catch(error => console.log(error));

Python (Requests)

import requests
import json

url = "https://go.getblock.io/<ACCESS-TOKEN>/"

payload = json.dumps({
    "jsonrpc": "2.0",
    "method": "get_tip_header",
    "params": [],
    "id": "getblock.io"
})

headers = {
    'Content-Type': 'application/json'
}

response = requests.post(url, headers=headers, data=payload)
print(response.text)

Rust (Reqwest)

use reqwest::Client;
use serde_json::json;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let client = Client::new();

    let payload = json!({
        "jsonrpc": "2.0",
        "method": "get_tip_header",
        "params": [],
        "id": "getblock.io"
});

    let response = client
        .post("https://go.getblock.io/<ACCESS-TOKEN>/")
        .header("Content-Type", "application/json")
        .json(&payload)
        .send()
        .await?;

    let result: serde_json::Value = response.json().await?;
    println!("{:#?}", result);

    Ok(())
}

Response Example

{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": {
        "compact_target": "0x1a08a97e",
        "dao": "0x40e8ea22a06a82822f9000c0d77b14002c5f3a0d4f8e4b07009fbd9f4d1f3909",
        "epoch": "0x707080a000ca6",
        "extra_hash": "0x0000000000000000000000000000000000000000000000000000000000000000",
        "hash": "0x02530b25ad0ff677acc365cb73de3e8cc09c7ddd58272e879252e199d08df83b",
        "nonce": "0x37b54e3aef60b89321e7e8b3ce0f4c2d",
        "number": "0xe5a45f",
        "parent_hash": "0x77fdd22f6ae8a717de9ae2b128834e9b2a1bb7e7387f01ddc278c6ec37ebaa05",
        "proposals_hash": "0x0000000000000000000000000000000000000000000000000000000000000000",
        "timestamp": "0x18f3b8d2a3c",
        "transactions_root": "0x6a7e8d3f1c4b9a2e5d8b7c4f9a3e6b1d5c8a2f4e7b1d6c9a3e5b8d2f4a6c8e0b",
        "version": "0x0"
    }
}

Response Parameters

Field	Type	Description
result.hash	H256	Hash of the tip block (32 bytes hex)
result.number	Uint64	Block number in hex
result.parent_hash	H256	Hash of the parent block
result.timestamp	Uint64	Unix timestamp in milliseconds (hex)
result.epoch	EpochNumberWithFraction	Packed epoch number, index, length
result.compact_target	Uint32	PoW difficulty target in compact form
result.dao	Byte32	Hash containing DAO-related fields (occupied capacity, accumulated rate, etc.)
result.nonce	Uint128	PoW nonce found by the miner
result.transactions_root	H256	Root of the Merkle tree of transactions
result.version	Uint32	Block version

Use Cases

• Polling for new tip blocks in indexers

• Light health checks before routing reads

• Tracking chain progression in monitoring dashboards

Error Handling

Status Code	Error Message	Cause
403	Forbidden	Missing or invalid <ACCESS-TOKEN>
-32602	Invalid params	Request parameters are missing or malformed
-32601	Method not found	Method does not exist or is not enabled on this node
-32603	Internal error	Server-side error while processing the request
429	Too Many Requests	Rate limit exceeded for your plan

SDK Integration

@ckb-lumos/lumos

import { RPC } from '@ckb-lumos/rpc';

const rpc = new RPC('https://go.getblock.io/<ACCESS-TOKEN>/');

// Lumos provides typed methods on `rpc` (e.g. rpc.getTipHeader(), rpc.getBlock(hash)).
// For raw access to any CKB RPC method:
const result = await rpc.send('get_tip_header', []);
console.log(result);

ckb-sdk-python / requests

# Using the official CKB SDK Python (ckb-sdk-python).
# For methods not yet wrapped, fall back to raw requests.
import requests

response = requests.post('https://go.getblock.io/<ACCESS-TOKEN>/', json={
    'jsonrpc': '2.0',
    'id': 'getblock.io',
    'method': 'get_tip_header',
    'params': []
}})
print(response.json())