Sign Raw Transaction

This method allows users to:

Create a signed UTXO raw transaction given unsigned hex, and optionally a set of prior transaction inputs.
Create a signed EVM raw transaction, given the destination address, amount and gas limit.

The transaction can then be broadcasted to the network using the send_raw_transaction to complete the process.

This method is used to sign a raw transaction that has already been created. For UTXO coins, the unsigned hex is required to sign the transaction. If prev_txns is not provided, it will be sourced via electrums.

Request Parameters

Structure	Type	Description
coin	string	The coin to sign the raw transaction with
type	string	The operation type. Accepted values: UTXO ( for utxo coins), ETH (for emv coins)
tx	object	A standard RawTxInfo object

Response Parameters

Structure	Type	Description
tx_hex	string	The signed transaction hex, ready for broadcast

Sign UTXO raw transaction hex

POST

sign_raw_transaction

{
  "userpass": "RPC_UserP@SSW0RD",
  "mmrpc": "2.0",
  "method": "sign_raw_transaction",
  "params": {
    "coin": "KMD",
    "type": "UTXO",
    "tx": {
      "tx_hex": "0400008085202f8901c8d6d8764e51bbadc0592b99f37b3b7d8c9719686d5a9bf63652a0802a1cd0360200000000feffffff0100dd96d8080000001976a914d346067e3c3c3964c395fee208594790e29ede5d88ac46366665000000000000000000000000000000"
    }
  },
  "id": 0
}

Response (success)

  {
    "mmrpc": "2.0",
    "result": {
      "tx_hex": "0400008085202f8901c8d6d8764e51bbadc0592b99f37b3b7d8c9719686d5a9bf63652a0802a1cd036020000006a47304402206b40df6d7b1d87622ea1eba0cdce09dfaf21556a408b2bd245920c2f3e9ff5e702201bd7bcc9587a9731cfd7c57057f173cbf635d2818263a96f211c413f6e83d187012103d8064eece4fa5c0f8dc0267f68cee9bdd527f9e88f3594a323428718c391ecc2feffffff0100dd96d8080000001976a914d346067e3c3c3964c395fee208594790e29ede5d88ac46366665000000000000000000000000000000"
    },
    "id":0
  }

Sign UTXO raw transaction hex with inputs

POST

sign_raw_transaction

{
  "userpass": "RPC_UserP@SSW0RD",
  "mmrpc": "2.0",
  "id": 0,
  "method": "sign_raw_transaction",
  "params": {
    "coin": "KMD",
    "type": "UTXO",
    "tx": {
      "tx_hex": "0400008085202f8901c8d6d8764e51bbadc0592b99f37b3b7d8c9719686d5a9bf63652a0802a1cd0360200000000feffffff0100dd96d8080000001976a914d346067e3c3c3964c395fee208594790e29ede5d88ac46366665000000000000000000000000000000",
      "prev_txns": [
        {
          "tx_hash": "36d01c2a80a05236f69b5a6d6819978c7d3b7bf3992b59c0adbb514e76d8d6c8",
          "index": 2,
          "script_pub_key": "76a914d346067e3c3c3964c395fee208594790e29ede5d88ac",
          "amount": 0.00001
        }
      ]
    }
  }
}

Response (success)

  {
    "mmrpc": "2.0",
    "result": {
      "tx_hex": "020000000001010d23d763f12d77a337cc16df2696ac3f48552dda373c9977fa1f5dd8d5025cb20100000000fdffffff01f40100000000000016001488accd2145b7232b958db5cdf09336ad619541e2024730440220156d185b3fb21725c040b7ddcf84bf862b46f079bb66067eef1941023b8451e602204d877ac51b74932dea34c20874fa8112b3636eb506ac429548f7c05fe54e3faf0121039ad38f67dbc22cf5a6bd48b26920d9fac71681836faf80a9a678ddbaa0fe92f800000000"
    },
    "id":0
  }

Signed an ETH/EVM raw transaction

POST

sign_raw_transaction

{
  "userpass": "RPC_UserP@SSW0RD",
  "mmrpc": "2.0",
  "id": 0,
  "method": "sign_raw_transaction",
  "params": {
    "coin": "MATIC",
    "type": "ETH",
    "tx": {
      "to": "0x927DaFDDa16F1742BeFcBEAE6798090354B294A9",
      "value": "0.85",
      "gas_limit": "21000",
      "pay_for_gas": {
        "tx_type": "Eip1559",
        "max_fee_per_gas": "1234.567",
        "max_priority_fee_per_gas": "1.2"
      }
    }
  }
}

Response (success)

  {
    "mmrpc": "2.0",
    "result": {
      "tx_hex": "f86680847735940083021000947bc1bbdd6a0a722fc9bffc49c921b685ecb84b948210008025a06c0ecbccf92caf5ac620b118f09a84a18c73d7b209e75696bb10e3c24c2dba64a055af3638f92daec1eb3057fb6a9ccf418325bb1aa6121a3314c3885100a5e63a"
    },
    "id": 0
  }

Once you have signed the raw transaction, dont forget to broadcast it to the network using the send_raw_transaction method.

Errors

Signing Error

You might see this if you try to sign a raw transaction that belongs to a different key pair.

{
  "mmrpc":"2.0",
  "error":"Signing error: with_key_pair:114] P2PKH script 'OP_DUP\nOP_HASH160\nOP_PUSHBYTES_20 0xd346067e3c3c3964c395fee208594790e29ede5d\nOP_EQUALVERIFY\nOP_CHECKSIG\n' built from input key pair doesn't match expected prev script 'OP_DUP\nOP_HASH160\nOP_PUSHBYTES_20 0x32311a35188a9439c6c866e842564d6fefd3a028\nOP_EQUALVERIFY\nOP_CHECKSIG\n'","error_path":"utxo_common","error_trace":"utxo_common:3144]",
  "error_type":"SigningError",
  "error_data":"with_key_pair:114] P2PKH script 'OP_DUP\nOP_HASH160\nOP_PUSHBYTES_20 0xd346067e3c3c3964c395fee208594790e29ede5d\nOP_EQUALVERIFY\nOP_CHECKSIG\n' built from input key pair doesn't match expected prev script 'OP_DUP\nOP_HASH160\nOP_PUSHBYTES_20 0x32311a35188a9439c6c866e842564d6fefd3a028\nOP_EQUALVERIFY\nOP_CHECKSIG\n'",
  "id":0
}

Invalid Request

{
  "mmrpc":"2.0",
  "error":"Error parsing request: invalid digit found in string",
  "error_path":"dispatcher",
  "error_trace":"dispatcher:108]",
  "error_type":"InvalidRequest",
  "error_data":"invalid digit found in string",
  "id":0
}

Invalid Parameter

{
  "mmrpc":"2.0",
  "error":"Invalid param: Invalid input length",
  "error_path":"eth",
  "error_trace":"eth:2544]",
  "error_type":"InvalidParam",
  "error_data":"Invalid input length",
  "id":0
}

No Such Coin

Coin does not exist or has not been activated.

{
  "mmrpc":"2.0",
  "error":"No such coin NOTSURE",
  "error_path":"lp_coins",
  "error_trace":"lp_coins:3965] lp_coins:3861]",
  "error_type":"NoSuchCoin",
  "error_data":{
    "coin":"NOTSURE"
  },
  "id":0
}

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Sign Raw Transaction