getblocktemplate - Bitcoin

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

This method returns data needed to construct a block to work on. It is used by miners to get a template for the next block.

Parameters

Parameter	Type	Required	Description
template_request	object	No	Template request parameters.
template_request.mode	string	No	Must be "template" or "proposal" (default: "template").
template_request.capabilities	array	No	Array of client capabilities (e.g., "longpoll", "coinbasetxn").
template_request.rules	array	No	Array of softfork rules to support.

Request

cURL

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

Axios

Request

Ruby

Response

{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": {
        "capabilities": ["proposal"],
        "version": 536870912,
        "rules": ["csv", "segwit", "taproot"],
        "vbavailable": {},
        "vbrequired": 0,
        "previousblockhash": "000000000000000000046b9302e08c16ea186950f42a5498320ddd1bd7ab3428",
        "transactions": [
            {
                "data": "0200000001...",
                "txid": "abc123...",
                "hash": "def456...",
                "depends": [],
                "fee": 25000,
                "sigops": 4,
                "weight": 900
            }
        ],
        "coinbaseaux": {"flags": ""},
        "coinbasevalue": 312500000,
        "longpollid": "000000000000000000046b9302e08c16ea186950f42a5498320ddd1bd7ab342812345",
        "target": "000000000000000000046b9302e08c16ea186950f42a5498000000000000000",
        "mintime": 1700000000,
        "mutable": ["time", "transactions", "prevblock"],
        "noncerange": "00000000ffffffff",
        "sigoplimit": 80000,
        "sizelimit": 4000000,
        "weightlimit": 4000000,
        "curtime": 1700001000,
        "bits": "170d21b9",
        "height": 820001,
        "default_witness_commitment": "6a24aa21a9ed..."
    }
}

Response Parameters

Field	Type	Description
version	number	Block version.
rules	array	Enabled softfork rules.
previousblockhash	string	Hash of current tip of the best chain.
transactions	array	Contents of non-coinbase transactions.
coinbaseaux	object	Data that should be included in coinbase scriptSig.
coinbasevalue	number	Maximum allowable coinbase value in satoshis.
target	string	The hash target.
mintime	number	Minimum timestamp appropriate for next block.
mutable	array	List of mutable template fields.
noncerange	string	Range of valid nonces.
sigoplimit	number	Limit of sigops per block.
sizelimit	number	Block size limit.
weightlimit	number	Block weight limit.
curtime	number	Current timestamp.
bits	string	Compressed target in compact format.
height	number	Height of the next block.
default_witness_commitment	string	Witness commitment for SegWit.

Use Case

The getblocktemplate method is essential for:

• Mining pool software integration

• Solo mining implementations

• Block construction optimization

• Mining software development

• Testing mining configurations

• Understanding block structure

Error Handling

Status Code	Error Message	Cause
403	Forbidden	Missing or invalid ACCESS-TOKEN.
-9	Node is downloading blocks	Initial block download in progress.
-10	Node is not connected	No peer connections available.

Integration Notes

The getblocktemplate method helps developers:

• Build mining pool backends

• Create solo mining software

• Implement stratum proxies

• Test block construction logic

• Analyze transaction selection algorithms