combinepsbt - Bitcoin Cash

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

This method merges multiple partially signed transactions for the same underlying transaction into a single PSBT, combining their signatures.

Parameters

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

Request

cURL

curl --location --request POST 'https://go.getblock.io/<ACCESS-TOKEN>/' \
--header 'Content-Type: application/json' \
--data-raw '{
    "jsonrpc": "2.0",
    "method": "combinepsbt",
    "params": [["cHNidP8BAHECAAAAAeJ+A9IdBRqivZ0zbDrAaTz6ks5xWSzuxSGxxIAZ/3ehAQAAAAD/////AqGaAQAAAAAAFgAUQiAC2SehyukB6sZoREzOjdCuYNUps7ELAAAAABepFPW0jREw3D02bR6r9ng6VS0cjgj0hwAAAAAAAAAA", "cHNidP8BAHECAAAAAeJ+A9IdBRqivZ0zbDrAaTz6ks5xWSzuxSGxxIAZ/3ehAQAAAAD/////AqGaAQAAAAAAFgAUQiAC2SehyukB6sZoREzOjdCuYNUps7ELAAAAABepFPW0jREw3D02bR6r9ng6VS0cjgj0hwAAAAAAAAAA"]],
    "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: 'combinepsbt',
  params: [[psbtA, psbtB]], 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': 'combinepsbt',
        'params': [["cHNidP8BAHECAAAAAeJ+A9IdBRqivZ0zbDrAaTz6ks5xWSzuxSGxxIAZ/3ehAQAAAAD/////AqGaAQAAAAAAFgAUQiAC2SehyukB6sZoREzOjdCuYNUps7ELAAAAABepFPW0jREw3D02bR6r9ng6VS0cjgj0hwAAAAAAAAAA", "cHNidP8BAHECAAAAAeJ+A9IdBRqivZ0zbDrAaTz6ks5xWSzuxSGxxIAZ/3ehAQAAAAD/////AqGaAQAAAAAAFgAUQiAC2SehyukB6sZoREzOjdCuYNUps7ELAAAAABepFPW0jREw3D02bR6r9ng6VS0cjgj0hwAAAAAAAAAA"]],
        '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": "combinepsbt",
            "params": [["cHNidP8BAHECAAAAAeJ+A9IdBRqivZ0zbDrAaTz6ks5xWSzuxSGxxIAZ/3ehAQAAAAD/////AqGaAQAAAAAAFgAUQiAC2SehyukB6sZoREzOjdCuYNUps7ELAAAAABepFPW0jREw3D02bR6r9ng6VS0cjgj0hwAAAAAAAAAA", "cHNidP8BAHECAAAAAeJ+A9IdBRqivZ0zbDrAaTz6ks5xWSzuxSGxxIAZ/3ehAQAAAAD/////AqGaAQAAAAAAFgAUQiAC2SehyukB6sZoREzOjdCuYNUps7ELAAAAABepFPW0jREw3D02bR6r9ng6VS0cjgj0hwAAAAAAAAAA"]],
            "id": "getblock.io"
        }))
        .send()
        .await?
        .json::<Value>()
        .await?;

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

Response

{
    "error": null,
    "id": "getblock.io",
    "result": "cHNidP8BAHECAAAAAeJ+A9IdBRqivZ0zbDrAaTz6ks5xWSzuxSGxxIAZ/3ehAQAAAAD/////AqGaAQAAAAAAFgAUQiAC2SehyukB6sZoREzOjdCuYNUps7ELAAAAABepFPW0jREw3D02bR6r9ng6VS0cjgj0hwAAAAAAAAAA"
}

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	Base64-encoded PSBT combining all inputs

Use Cases

• Multisig Aggregation: Merge signatures from separate co-signers into one PSBT

• Distributed Signing: Collect partial signatures produced independently

• Threshold Wallets: Assemble the required signatures for an m-of-n spend

• Workflow Completion: Consolidate a PSBT before finalizing it

Error Handling

Error Code	Message	Description
-22	Decode failed	The supplied data could not be decoded
-8	Invalid parameter	A required parameter is missing or malformed
-32603	Internal error	Node failed to process the request