estimatesmartfee - Bitcoin

Example code for the estimatesmartfee JSON RPC method. Сomplete guide on how to use estimatesmartfee JSON RPC in GetBlock Web3 documentation.

This method estimates the approximate fee per kilobyte needed for a transaction to begin confirmation within a given number of blocks.

Parameters

Parameter	Type	Required	Description
conf_target	number	Yes	Confirmation target in blocks (1 - 1008).
estimate_mode	string	No	The fee estimate mode: "unset", "economical", or "conservative" (default: "conservative").

Request

cURL

curl --location --request POST 'https://go.getblock.io/<ACCESS-TOKEN>/' \
--header 'Content-Type: application/json' \
--data-raw '{
    "jsonrpc": "2.0",
    "method": "estimatesmartfee",
    "params": [6, "economical"],
    "id": "getblock.io"
}'

Response

{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": {
        "feerate": 0.00012345,
        "blocks": 6
    }
}

Response Parameters

Field	Type	Description
feerate	number	Estimate fee rate in BTC/kB (1 kB = 1000 bytes).
blocks	number	Block number where estimate was found.
errors	array	Errors encountered during processing (if any).

Use Case

The estimatesmartfee method is essential for:

• Dynamic fee calculation for transactions

• Building user fee selection interfaces

• Implementing RBF (Replace-By-Fee) strategies

• Optimizing transaction costs

• Supporting various confirmation time preferences

• Building fee estimation dashboards

Error Handling

Status Code	Error Message	Cause
403	Forbidden	Missing or invalid ACCESS-TOKEN.
-1	Insufficient data	Not enough data to make an estimate.

Integration Notes

The estimatesmartfee method helps developers:

• Build dynamic fee calculators

• Implement priority-based fee selection

• Create cost-optimized transaction systems

• Support time-sensitive transactions

• Build fee comparison tools