Filecoin.GasEstimateMessageGas - Filecoin

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

This method fills in the unset gas fields of a message, estimating the gas limit, fee cap, and premium needed for timely inclusion. The message is returned with its gas fields populated.

Parameters

Parameter	Type	Required	Description
message	object	Yes	The message to estimate gas for
sendSpec	object	No	Optional send specification, such as a max fee; null to omit
tipsetKey	array	Yes	Tipset key to estimate against; empty array for the chain head

Request

cURL

curl --location --request POST 'https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/' \
--header 'Content-Type: application/json' \
--data-raw '{"jsonrpc": "2.0", "method": "Filecoin.GasEstimateMessageGas", "params": [{"To": "f1ne72cbn6r55wea7ifjv4ypyti7t2df5dumsjhzq", "From": "f3ukhj6tpkgxjknu54opiaej2vrjz7nh7gzodkqlhpfphc6gxkogzmojv2cnlpgcuwkvnyhloctnc6lmlvceuq", "Value": "1000000000000000000", "Method": 0}, null, []], "id": "getblock.io"}'

JavaScript

example.js

const response = await fetch('https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({
        jsonrpc: '2.0',
        method: 'Filecoin.GasEstimateMessageGas',
        params: [{"To": "f1ne72cbn6r55wea7ifjv4ypyti7t2df5dumsjhzq", "From": "f3ukhj6tpkgxjknu54opiaej2vrjz7nh7gzodkqlhpfphc6gxkogzmojv2cnlpgcuwkvnyhloctnc6lmlvceuq", "Value": "1000000000000000000", "Method": 0}, null, []],
        id: 'getblock.io'
    })
});

const data = await response.json();
console.log(data.result);

Python

example.py

import requests

response = requests.post(
    'https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/',
    headers={'Content-Type': 'application/json'},
    json={
        'jsonrpc': '2.0',
        'method': 'Filecoin.GasEstimateMessageGas',
        'params': [{"To": "f1ne72cbn6r55wea7ifjv4ypyti7t2df5dumsjhzq", "From": "f3ukhj6tpkgxjknu54opiaej2vrjz7nh7gzodkqlhpfphc6gxkogzmojv2cnlpgcuwkvnyhloctnc6lmlvceuq", "Value": "1000000000000000000", "Method": 0}, null, []],
        'id': 'getblock.io'
    }
)

print(response.json()['result'])

Response

{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": {
        "To": "f1ne72cbn6r55wea7ifjv4ypyti7t2df5dumsjhzq",
        "From": "f3ukhj6tpkgxjknu54opiaej2vrjz7nh7gzodkqlhpfphc6gxkogzmojv2cnlpgcuwkvnyhloctnc6lmlvceuq",
        "Value": "1000000000000000000",
        "GasLimit": 2200000,
        "GasFeeCap": "101520",
        "GasPremium": "100178",
        "Method": 0,
        "Nonce": 43
    }
}

Response Parameters

Field	Type	Description
GasLimit	integer	Estimated maximum gas units for the message
GasFeeCap	string	Estimated maximum fee per gas unit, in attoFIL
GasPremium	string	Estimated priority fee per gas unit, in attoFIL
Nonce	integer	Nonce assigned to the message

Use Cases

• Fee Estimation: Populate gas fields before signing a message

• Cost Preview: Show the estimated cost of a message

• Inclusion Tuning: Set gas for timely block inclusion

• Wallet Flows: Prepare a fully specified message for signing

Error Handling

Error Code	Message	Description
-32602	Invalid params	A parameter is missing or has the wrong type or format
1	Actor not found	The address or actor does not exist in the requested tipset
-32603	Internal error	The node failed to process the request