UTXO - Making a transaction

Modified on Wed, 15 Feb 2023 at 10:32 AM

Bitcoin, Litecoin, Doge, ... and other UTXO-based chains have several ways to make transactions.

Examples

Let's say address_x contains 100BTC and you want to make a tx from address_x to address_y of 10BTC.

Considering what's possible, we can make a BTC transfer as follows.

Default transfer type:

curl --location --request POST 'https://api.tatum.io/v3/bitcoin/transaction' \
--header 'x-api-key: ##API_KEY' \
--header 'Content-Type: application/json' \
--data-raw '{
    "fromAddress": [
        {
            "address": "address_x",
            "privateKey": "pk_address_x"
        }
    ],
    "to": [
        {
            "address": "address_x", // rest of coin back to original address, IF that's what you want.
            "value": 89.87654321 // Here you also consider the amount of "fee" you will allocate for the "miners"
        },
        {
            "address": "address_y", // where you want to transfer those "complete" 10BTC
            "value": 10
        }
    ]
  }'

// within the "to" IF you only have x1 address as destination && don't specify where the rest of the coins go, the blockchain considers that amount as the "fee" to be given to the miner.

Using fromUTXO with fee && changeAddress:

curl --location --request POST 'https://api.tatum.io/v3/bitcoin/transaction' \
--header 'x-api-key: ##API_KEY' \
--header 'Content-Type: application/json' \
--data-raw '{
  "fromUTXO":[
      {
        "txHash":"######",
        "index":##, // the index of the "PublicAddress" within that "txHash"
        "privateKey":"pk_address_x"
      }
    ],
   "to": [ // this is an array, you can have multiple destinations
      {
        "address":"address_y", //main destination address
        "value":10
      }
    ],
  "changeAddress":"address_x", //where you sent the rest "unspent" coin back
  "fee":"0.87654321" // this fee is quite high for BTC or LTC, take it as an example. Also, max decimals is 8
}'

Good to know

We strongly encourage all our customers to try this out with their testnet API keys with coins from a faucet.

Find popular faucets available at the following link.