getbestblockhash - Bitcoin Cash

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

This method returns the hash of the best (tip) block in the most-work fully-validated chain. This is the primary method for finding the current chain tip.

Parameters

This method does not accept any parameters.

Request

cURL

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

bitcoinjs-lib

example.js

const axios = require('axios');
// bitcoinjs-lib handles key and transaction construction; chain queries go through the node RPC.
const { data } = await axios.post('https://go.getblock.io/<ACCESS-TOKEN>/', {
  jsonrpc: '2.0', method: 'getbestblockhash', params: [], id: 'getblock.io'
});
console.log(data.result);

Request

example.py

import requests

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

print(response.json()['result'])

Rust

example.rs

use reqwest::Client;
use serde_json::{json, Value};

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

    let response = client
        .post("https://go.getblock.io/<ACCESS-TOKEN>/")
        .header("Content-Type", "application/json")
        .json(&json!({
            "jsonrpc": "2.0",
            "method": "getbestblockhash",
            "params": [],
            "id": "getblock.io"
        }))
        .send()
        .await?
        .json::<Value>()
        .await?;

    println!("Result: {}", response["result"]);
    Ok(())
}

Response

{
    "error": null,
    "id": "getblock.io",
    "result": "0000000000000000023a561e1ea370153aac5d1504726d1a039032831c05fcfc"
}

Response Parameters

Parameter	Type	Description
error	null|object	Error object when the call fails, otherwise null
id	string	Request identifier matching the request
result	string	Hex-encoded hash of the current chain tip block

Use Cases

• Tip Tracking: Poll the chain tip to detect newly connected blocks

• Reorg Detection: Compare successive tip hashes to spot a chain reorganization

• Sync Checks: Confirm an application is reading from the current chain head

• Header Fetch: Feed the returned hash into getblockheader for tip metadata

Error Handling

Error Code	Message	Description
-32700	Parse error	Request body is not valid JSON
-32600	Invalid request	The JSON sent is not a valid request object
-32603	Internal error	Node failed to read the requested chain state