getblocktemplate - Bitcoin Cash

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

This method returns data needed to construct a block to work on, following the getblocktemplate mining protocol. It is used by mining software to assemble candidate blocks.

Parameters

Parameter	Type	Required	Description
template_request	object	No	Object specifying template mode, capabilities, and supported rules

Request

cURL

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

bitcoinjs-lib

example.js

const axios = require('axios');
const { data } = await axios.post('https://go.getblock.io/<ACCESS-TOKEN>/', {
  jsonrpc: '2.0', method: 'getblocktemplate',
  params: [{ rules: ['csv', 'segwit'] }], id: 'getblock.io'
});
console.log(data.result.height, data.result.target);

Request

example.py

import requests

response = requests.post(
    'https://go.getblock.io/<ACCESS-TOKEN>/',
    headers={'Content-Type': 'application/json'},
    json={
        'jsonrpc': '2.0',
        'method': 'getblocktemplate',
        'params': [{"rules": ["csv", "segwit"]}],
        '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": "getblocktemplate",
            "params": [{"rules": ["csv", "segwit"]}],
            "id": "getblock.io"
        }))
        .send()
        .await?
        .json::<Value>()
        .await?;

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

Response

{
    "error": null,
    "id": "getblock.io",
    "result": {
        "version": 536870912,
        "previousblockhash": "0000000000000000023a561e1ea370153aac5d1504726d1a039032831c05fcfc",
        "height": 684635,
        "curtime": 1617180999,
        "bits": "170cdf6f",
        "target": "000000000000000000073da8...",
        "coinbasevalue": 625000000,
        "mintime": 1617176374,
        "sizelimit": 32000000,
        "transactions": []
    }
}

Response Parameters

Parameter	Type	Description
error	null|object	Error object when the call fails, otherwise null
id	string	Request identifier matching the request
result	object	Block template object for mining

Result Object

Field	Type	Description
version	numeric	Block version
previousblockhash	string	Hash of the current tip to build on
height	numeric	Height of the block to be mined
coinbasevalue	numeric	Maximum coinbase value in satoshis
target	string	The proof-of-work target as a hex string
transactions	array	Transactions to include in the block

Use Cases

• Mining Software: Feed block templates into a mining worker

• Pool Operation: Assemble candidate blocks for pool participants

• Coinbase Construction: Read coinbasevalue to build the coinbase transaction

• Template Monitoring: Track template changes as the mempool updates

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