Bitcoin Core RPC Commands: Creating a Block with Coinbase Address

The Bitcoin Core (BTC) node provides a RESTful API for interacting with the blockchain. One useful feature is the ability to generate a block using an input address and other parameters. In this article, we’ll explore two separate commands that can help you construct the block body and its Merkle root based on your provided address.

Command 1: Generate Block Body

The bitcoin-cli command-line tool used by the Bitcoin Core node allows you to generate a new block using the generateblock subcommand. The --input flag is required when specifying an input address. Here’s how you can use this command:

bitcoin-cli generateblock --input 1M9BtEeVzKv6W9qF5f3Pn7y8J9ZdJc1Tf -m 2

This will generate a new block with the input address 1M9BtEeVzKv6W9qF5f3Pn7y8J9ZdJc1Tf and a merkle root that can be verified using other commands.

Command 2: Generate Merkle Root

The bitcoin-cli tool also provides the getblocktemplate subcommand, which allows you to generate a block template with a specified input address. The -m flag is required when specifying an output format (in this case, merkle root). Here’s how you can use this command:

bitcoin-cli getblocktemplate -m 2 --input 1M9BtEeVzKv6W9qF5f3Pn7y8J9ZdJc1Tf

This will generate a block template with the specified input address, and you can then use other commands to create the actual block.

Verifying Coinbase Address in a New Block

To verify that the bitcoin-cli tool is generating a block including your input address, you can use the following command:

bitcoin-cli gettransaction -id 1234567890 --address 1M9BtEeVzKv6W9qF5f3Pn7y8J9ZdJc1Tf

This will query the blockchain for a transaction with the specified input address. The bitcoin-cli tool should output the transaction details, including the Merkle root.

Example Use Case

Let’s say you want to create a new block that includes your input address 1M9BtEeVzKv6W9qF5f3Pn7y8J9ZdJc1Tf and its merkle root. You can use the following commands:

Generate block body

bitcoin-cli generateblock --input 1M9BtEeVzKv6W9qF5f3Pn7y8J9ZdJc1Tf -m 2



Get block template with merkle root

bitcoin-cli getblocktemplate -m 2 --input 1M9BtEeVzKv6W9qF5f3Pn7y8J9ZdJc1Tf > block_template.json



Generate transaction for the new block

bitcoin-cli sendrawtransaction -txn -address 1M9BtEeVzKv6W9qF5f3Pn7y8J9ZdJc1Tf --outputchain 

This will create a new transaction that includes the input address and its merkle root, which can then be used to construct a new block.