joinpsbts - Bitcoin

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

This method combines multiple distinct PSBTs with distinct inputs and outputs into a single PSBT that incorporates inputs and outputs from all the PSBTs. No input in any of the PSBTs can be in more than one of the PSBTs.

Parameters

Parameter	Type	Required	Description
txs	array	Yes	An array of base64 strings of PSBTs to join.

Request

cURL

curl --location --request POST 'https://go.getblock.io/<ACCESS-TOKEN>/' \
--header 'Content-Type: application/json' \
--data-raw '{
    "jsonrpc": "2.0",
    "method": "joinpsbts",
    "params": [["cHNidP8BAHUCAAAAASaBcTce...", "cHNidP8BAHUCAAAAATaBdTdf..."]],
    "id": "getblock.io"
}'

Axios

Request

Rust

Response

{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": "cHNidP8BAHsCAAAAAgaBcTce3/KF6Tig7cez..."
}

Response Parameters

Field	Type	Description
result	string	The base64-encoded PSBT containing all joined inputs and outputs.

Use Case

The joinpsbts method is essential for:

• CoinJoin transaction construction

• Payment batching from multiple sources

• Multi-party transaction building

• Collaborative spending protocols

• Privacy-enhancing transaction techniques

• Complex payment channel operations

Error Handling

Status Code	Error Message	Cause
403	Forbidden	Missing or invalid ACCESS-TOKEN.
-8	Inputs overlap	One or more inputs appear in multiple PSBTs.
-25	Error parsing PSBT	One or more PSBT strings are invalid.

Integration With Web3

The joinpsbts method helps developers:

• Build CoinJoin implementations

• Create multi-party payment systems

• Implement payment batching

• Support collaborative transaction protocols

• Build privacy-focused applications