createpsbt - Bitcoin

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

This method creates an empty Partially Signed Bitcoin Transaction (PSBT) from a set of inputs and outputs, returning it as a base64 string.

Parameters

Parameter	Type	Required	Description
inputs	array	Yes	Inputs, each with a txid and vout
outputs	array	Yes	Outputs mapping addresses to amounts, or data outputs
locktime	number	No	Raw locktime (default: 0)
replaceable	boolean	No	Whether the transaction signals RBF (default: false)

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": "createpsbt",
    "params": [[{"txid": "4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b", "vout": 0}], [{"bc1qar0srrr7xfkvy5l643lydnw9re59gtzzwf5mdq": 6.24}]],
    "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: 'createpsbt',
    params: [[{"txid": "4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b", "vout": 0}], [{"bc1qar0srrr7xfkvy5l643lydnw9re59gtzzwf5mdq": 6.24}]],
    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': 'createpsbt',
        'params': [[{"txid": "4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b", "vout": 0}], [{"bc1qar0srrr7xfkvy5l643lydnw9re59gtzzwf5mdq": 6.24}]],
        '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": "createpsbt",
            "params": [[{"txid": "4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b", "vout": 0}], [{"bc1qar0srrr7xfkvy5l643lydnw9re59gtzzwf5mdq": 6.24}]],
            "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 base64-encoded PSBT

Use Cases

• PSBT Workflows: Create a PSBT for multi-party signing

• Hardware Wallets: Build a PSBT for device signing

• Custody Systems: Prepare PSBTs for offline signers

• Coordination: Start a collaborative transaction

Error Handling

Error Code	Message	Description
403	Forbidden	Missing or invalid ACCESS-TOKEN
-8	Invalid parameter	A parameter is out of range or malformed
-32601	Method not found	The method is not available on this endpoint
-32602	Invalid params	A parameter is missing or has the wrong type