PSBTs

PSBTs are a format for communicating and collaboratively working with transactions.

The format is defined in BIP-0174: https://github.com/bitcoin/bips/blob/master/bip-0174.mediawiki

Methods

An ECPair object is required for some methods:

const tinysecp = require('tiny-secp256k1');

const ECPair = await import('ecpair')

const ecp = ECPair.ECPairFactory(tinysecp);

combinePsbts

Combine multiple PSBTs

{
  ecp: <ECPair Object>
  psbts: [<BIP 174 Encoded PSBT Hex String>]
}

@throws
<Combine PSBT Error>

@returns
{
  psbt: <BIP 174 Encoded PSBT Hex String>
}

createPsbt

Create a PSBT

{
  outputs: [{
    script: <Output ScriptPub Hex String>
    tokens: <Sending Tokens Number>
  }]
  utxos: [{
    id: <Transaction Id Hex String>
    [sequence]: <Sequence Number>
    vout: <Output Index Number>
  }]
  [timelock]: <Set Lock Time on Transaction To Number>
  [version]: <Transaction Version Number>
}

@returns
{
  psbt: <Partially Signed Bitcoin Transaction Hex Encoded String>
}

decodePsbt

Decode a BIP 174 encoded PSBT

{
  ecp: <ECPair Object>
  psbt: <Hex Encoded Partially Signed Bitcoin Transaction String>
}

@throws
<Invalid PSBT Error>

@returns
{
  inputs: [{
    [bip32_derivations]: [{
      fingerprint: <Public Key Fingerprint Hex String>
      [leaf_hashes]: <Taproot Leaf Hash Hex String>
      path: <BIP 32 Child / Hardened Child / Index Derivation Path String>
      public_key: <Public Key Hex String>
    }]
    [final_scriptsig]: <Final ScriptSig Hex String>
    [final_scriptwitness]: <Final Script Witness Hex String>
    [non_witness_utxo]: <Non-Witness Hex Encoded Transaction String>
    [partial_sig]: [{
      hash_type: <Signature Hash Type Number>
      public_key: <Public Key Hex String>
      signature: <Signature Hex String>
    }]
    [redeem_script]: <Hex Encoded Redeem Script String>
    [sighash_type]: <Sighash Type Number>
    [taproot_control_block]: <Taproot Script Spend Control Block Hex String>
    [taproot_leaf_hash]: <Taproot Leaf Hash Hex String>
    [taproot_leaf_public_key]: <Leaf Script X Only Public Key Hex String>
    [taproot_leaf_script]: <Taproot Leaf Spend Script Hex String>
    [taproot_leaf_version]: <Taproot Leaf Spend Script Version Number>
    [taproot_internal_key]: <X Only Taproot Internal Public Key Hex String>
    [taproot_key_spend_sig]: <Taproot Key Spend Signature Hex String>
    [taproot_root_hash]: <Taproot Merkle Root Hash Hex String>
    [taproot_script_signature]: <Taproot Script Spend Script Hex String>
    [unrecognized_attributes]: [{
      type: <Key Type Hex String>
      value: <Value Hex String>
    }]
    [witness_script]: <Witness Script Hex String>
    [witness_utxo]: {
      script_pub: <UTXO ScriptPub Hex String>
      tokens: <Tokens Number>
    }
  }]
  outputs: [{
    [bip32_derivation]: {
      fingerprint: <Public Key Fingerprint Hex String>
      [leaf_hashes]: <Taproot Leaf Hash Hex String>
      path: <BIP 32 Child/HardenedChild/Index Derivation Path Hex String>
      public_key: <Public Key Hex String>
    }
    [redeem_script]: <Hex Encoded Redeem Script>
    [taproot_internal_key]: <X Only Taproot Internal Public Key Hex String>
    [taproot_script_tree]: [{
      depth: <Tree Depth Number>
      script: <Leaf Script Hex String>
      version: <Leaf Script Version Number>
    }]
    [unrecognized_attributes]: [{
      type: <Key Type Hex String>
      value: <Value Hex String>
    }]
    [witness_script]: <Hex Encoded Witness Script>
  }]
  pairs: [{
    type: <Key Type Hex String>
    value: <Value Hex String>
  }]
  [unrecognized_attributes]: [{
    type: <Global Key Type Hex String>
    value: <Global Value Hex String>
  }]
  unsigned_transaction: <Unsigned Transaction Hex String>
}

encodePsbt

Encode a Partially Signed Bitcoin Transaction

{
  pairs: [{
    [separator]: <Is Separator Bool>
    [type]: <Type Buffer Object>
    [value]: <Value Buffer Object>
  }]
}

@throws
<Failed To Encode Error>

@returns
{
  psbt: <Hex Encoded Partially Signed Bitcoin Transaction String>
}

extractTransaction

Extract a transaction from a finalized PSBT

{
  ecp: <ECPair Object>
  psbt: <BIP 174 Encoded PSBT Hex String>
}

@throws
<Extract Transaction Error>

@returns
{
  transaction: <Hex Serialized Transaction String>
}

finalizePsbt

Finalize the inputs of a PSBT

{
  ecp: <ECPair Object>
  psbt: <BIP 174 Encoded PSBT Hex String>
}

@throws
<Finalize PSBT Error>

@returns
{
  psbt: <BIP 174 Encoded PSBT Hex String>
}

signPsbt

Update a PSBT with signatures

{
  ecp: <ECPair Object>
  network: <Network Name String>
  psbt: <BIP 174 Encoded PSBT Hex String>
  signing_keys: [<WIF Encoded Private Key String>]
}

@throws
<Sign PSBT Error>

@returns
{
  psbt: <BIP 174 Encoded PSBT Hex String>
}

transactionAsPsbt

Convert a signed transaction to a signed PSBT

Note: not all signed transactions can be converted to a signed PSBT. For example, a preimage cannot be represented in a standard PSBT.

{
  ecp: <ECPair Object>
  spending: [<Spending Transaction Hex String>]
  transaction: <Hex Encoded Transaction String>
}

@throws
<Error>

@returns
{
  psbt: <Signed PSBT String>
}

updatePsbt

Update a PSBT

{
  [additional_attributes]: [{
    type: <Type Hex String>
    value: <Value Hex String>
    vin: <Input Index Number>
    vout: <Output Index Number>
  }]
  [bip32_derivations]: [{
    fingerprint: <BIP 32 Fingerprint of Parent's Key Hex String>
    path: <BIP 32 Derivation Path String>
    public_key: <Public Key String>
  }]
  ecp: <ECPair Object>
  psbt: <BIP 174 Encoded PSBT String>
  [redeem_scripts]: [<Hex Encoded Redeem Script String>]
  [sighashes]: [{
    id: <Transaction Id String>
    sighash: <Sighash Flag Number>
    vout: <Spending Output Index Number>
  }]
  [signatures]: [{
    vin: <Signature Input Index Number>
    hash_type: <Signature Hash Type Number>
    public_key: <BIP 32 Public Key String>
    signature: <Signature Hex String>
  }]
  [taproot_inputs]: [{
    vin: <Input Index Number>
    [key_spend_sig]: <Taproot Key Spend Signature Hex String>
  }]
  [transactions]: [<Hex Encoding Transaction String>]
  [witness_scripts]: [<Witness Script String>]
}

@throws
<Update PSBT Error>

@returns
{
  psbt: <Hex Encoded Partially Signed Bitcoin Transaction String>
}