combinepsbt - Bitcoin

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

This method combines multiple PSBTs of the same transaction into one, merging the data each contains. It is used to gather signatures from multiple signers.

Parameters

Parameter	Type	Required	Description
txs	array	Yes	The base64-encoded PSBTs to combine

Request

cURL

curl --location --request POST 'https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/' \
--header 'Content-Type: application/json' \
--data-raw '{
    "jsonrpc": "2.0",
    "method": "combinepsbt",
    "params": [["cHNidP8BAHUCAAAAASaBcTce3/KF6Tet7qSze3gADAVmy7OtZGQXE8pCFxv2AAAAAAD+////AtPf9QUAAAAAGXapFPUKlXhpm/rZ4JBKZ2n3nQ4jCMYBiKz1AAAAAA==", "cHNidP8BAHUCAAAAASaBcTce3/KF6Tet7qSze3gADAVmy7OtZGQXE8pCFxv2AAAAAAD+////AtPf9QUAAAAAGXapFPUKlXhpm/rZ4JBKZ2n3nQ4jCMYBiKz1AAAAAA=="]],
    "id": "getblock.io"
}'

bitcoinjs-lib

example.js

const axios = require('axios');

const response = await axios.post('https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/', {
    jsonrpc: '2.0',
    method: 'combinepsbt',
    params: [["cHNidP8BAHUCAAAAASaBcTce3/KF6Tet7qSze3gADAVmy7OtZGQXE8pCFxv2AAAAAAD+////AtPf9QUAAAAAGXapFPUKlXhpm/rZ4JBKZ2n3nQ4jCMYBiKz1AAAAAA==", "cHNidP8BAHUCAAAAASaBcTce3/KF6Tet7qSze3gADAVmy7OtZGQXE8pCFxv2AAAAAAD+////AtPf9QUAAAAAGXapFPUKlXhpm/rZ4JBKZ2n3nQ4jCMYBiKz1AAAAAA=="]],
    id: 'getblock.io'
}, {
    headers: { 'Content-Type': 'application/json' }
});

console.log(response.data.result);

Request

example.py

import requests

response = requests.post(
    'https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/',
    headers={'Content-Type': 'application/json'},
    json={
        'jsonrpc': '2.0',
        'method': 'combinepsbt',
        'params': [["cHNidP8BAHUCAAAAASaBcTce3/KF6Tet7qSze3gADAVmy7OtZGQXE8pCFxv2AAAAAAD+////AtPf9QUAAAAAGXapFPUKlXhpm/rZ4JBKZ2n3nQ4jCMYBiKz1AAAAAA==", "cHNidP8BAHUCAAAAASaBcTce3/KF6Tet7qSze3gADAVmy7OtZGQXE8pCFxv2AAAAAAD+////AtPf9QUAAAAAGXapFPUKlXhpm/rZ4JBKZ2n3nQ4jCMYBiKz1AAAAAA=="]],
        'id': 'getblock.io'
    }
)

print(response.json())

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://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/")
        .header("Content-Type", "application/json")
        .json(&json!({
            "jsonrpc": "2.0",
            "method": "combinepsbt",
            "params": [["cHNidP8BAHUCAAAAASaBcTce3/KF6Tet7qSze3gADAVmy7OtZGQXE8pCFxv2AAAAAAD+////AtPf9QUAAAAAGXapFPUKlXhpm/rZ4JBKZ2n3nQ4jCMYBiKz1AAAAAAD+////AtPf9QUAAAAAGXapFPUKlXhpm/rZ4JBKZ2n3nQ4jCMYBiKz1AAAAAA=="]],
            "id": "getblock.io"
        }))
        .send()
        .await?
        .json::<Value>()
        .await?;

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

Response

{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": "cHNidP8BAHUCAAAAASaBcTce3/KF6Tet7qSze3gADAVmy7OtZGQXE8pCFxv2AAAAAAD+////AtPf9QUAAAAAGXapFPUKlXhpm/rZ4JBKZ2n3nQ4jCMYBiKz1AAAAAA=="
}

Response Parameters

Parameter	Type	Description
jsonrpc	string	JSON-RPC protocol version ("2.0")
id	string	Request identifier matching the request
result	string	The combined base64-encoded PSBT

Use Cases

• Multisig Signing: Merge PSBTs from multiple signers

• Coordination: Combine partial signatures

• Custody: Assemble signatures from separate devices

• Workflows: Consolidate a distributed signing round

Error Handling

Error Code	Message	Description
403	Forbidden	Missing or invalid ACCESS-TOKEN
-22	Decode failed	The transaction or script could not be decoded
-8	Invalid parameter	A parameter is out of range or malformed
-32602	Invalid params	A parameter is missing or has the wrong type