The Fireblocks JSON-RPC is a command-line server that utilizes the Fireblocks API to facilitate interactions with Ethereum Virtual Machine (EVM) chains. It enables users to perform blockchain operations through a JSON-RPC interface, and it was developed to simplify the integration of Fireblocks' secure wallet infrastructure with blockchain applications.

In this article, you will find installation instructions, code examples, and guidance on how to utilize Fireblocks JSON RPC and other frameworks (e.g. Brownie, Foundry) for smart contract development and interactions.

Getting Started

web3.py integration

Fireblocks JSON-RPC helps seamlessly integrate Fireblocks into your web3.py development stack.

You can use it to deploy contracts, sign messages, and send transactions.


npm install -g @fireblocks/fireblocks-json-rpc
pip install web3


Set the environment variables.

Create example.py:

import json
import os
from datetime import datetime
from web3 import Web3

web3 = Web3(Web3.IPCProvider(os.environ['FIREBLOCKS_JSON_RPC_ADDRESS'], 60000*180))
web3.eth.defaultAccount = web3.eth.accounts[0]
CONTRACT_ADDRESS = Web3.toChecksumAddress("0x8A470A36a1BDE8B18949599a061892f6B2c4fFAb")
GREETER_ABI = json.loads('[{"inputs":[{"internalType":"string","name":"_greeting","type":"string"}],"stateMutability":"nonpayable","type":"constructor"},{"inputs":[],"name":"greet","outputs":[{"internalType":"string","name":"","type":"string"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"string","name":"_greeting","type":"string"}],"name":"setGreeting","outputs":[],"stateMutability":"nonpayable","type":"function"}]')
GREETING = "Hello web3! By " + web3.eth.defaultAccount + " at " + str(datetime.now())

if __name__ == '__main__':
    print('last block number: ', web3.eth.blockNumber)
    for account in web3.eth.accounts:
        print('account: ', account)
        print('account balance: ', web3.fromWei(web3.eth.getBalance(account), "ether"), ' ETH\n')

    print('Greeter contract: https://sepolia.etherscan.io/address/' + CONTRACT_ADDRESS)
  	contract = web3.eth.contract(address=CONTRACT_ADDRESS, abi=GREETER_ABI)

    print('Current greeting:', contract.functions.greet().call())
    print('Setting greeting to:', GREETING)
    tx_hash = contract.functions.setGreeting(GREETING).transact({'from':web3.eth.defaultAccount})
    print('Transaction signed and broadcasted: https://sepolia.etherscan.io/tx/' + tx_hash.hex())
    print('Waiting for transaction to be mined...')

    print('Current greeting:', contract.functions.greet().call())


fireblocks-json-rpc -- python example.py

You can now use the web3 object exactly as you normally would!

Ethereum Smart Contract Development

Using Brownie

Use the Fireblocks JSON-RPC to seamlessly work with Brownie on top of Fireblocks.


Step 1 - Brownie installation:

Please follow the Brownie official documentation for installation

Step 2 - Install Fireblocks JSON RPC server:

npm install -g @fireblocks/fireblocks-json-rpc


Step 1 - Create a new example Brownie project:

brownie bake token
cd token

Step 2 - set environment variables:

Set the environment variables

Step 3 - Add Fireblocks Sepolia network to Brownie:

brownie networks add Fireblocks fireblocks-sepolia name="Sepolia (Fireblocks)" chainid=11155111 host='${FIREBLOCKS_API_KEY}' timeout=600

Step 4 - Configure brownie-config.yaml file:

Add dotenv: .env parameter to the config yaml file.


# exclude SafeMath when calculating test coverage
# https://eth-brownie.readthedocs.io/en/v1.10.3/config.html#exclude_paths
    - SafeMath
dotenv: .env


fireblocks-json-rpc -- brownie run --network fireblocks-sepolia scripts/token.py

Using Foundry

Installing Foundry

You can skip this section if you already have Foundry installed or follow that Foundry Installation guide , Foundry New Project guide on the Foundry website for all details.

We provide you with a very basic process here for convenience:

curl -L https://foundry.paradigm.xyz | bash
forge init hello_foundry
cd hello_foundry
forge build
forge test

After you complete these steps, you'll have a new Foundry project.

Foundry integration

The Fireblocks Local JSON-RPC helps seamlessly integrate Fireblocks into your Foundry development stack.

You can use it to deploy contracts, sign messages, and send transactions.


npm install -g @fireblocks/fireblocks-json-rpc


Configuration can be set via command line flags or environment variables.

Command line flags:

  • Ignore apiBaseUrl if you are not using a sandbox environment
fireblocks-json-rpc --apiKey <key> --privateKey <path_or_contents> --chainId <chainId> --apiBaseUrl https://sandbox-api.fireblocks.io

Environment variables:

  • Ignore FIREBLOCKS_API_BASE_URL if you are not using a sandbox environment

Delete the files that came with your Foundry boilerplate template:

rm test/Counter.t.sol script/Counter.s.sol src/Counter.sol

Deploy Contract - Using 'forge script'

Now that you have a Foundry project set up, create your smart contract src/Hello.sol in the project folder and then deploy it to the Sepolia Ethereum Testnet.

Step 1: Create and compile the Solidity file

pragma solidity ^0.8.17;

contract HelloWorld {
    string public greet = "Hello World!";

Run the following command to compile it:

forge build

Step 2: Create the deployment script

Create a deployment script script/Hello.s.sol :

pragma solidity ^0.8.17;

import "forge-std/Script.sol";
import "../src/Hello.sol";

contract MyScript is Script {
    function run() external {

        HelloWorld hello = new HelloWorld();


Step 3: Deploy smart contract

Deploy your contract to the Ethereum Sepolia Testnet (It is recommended to use the --slow parameter in your forge script command, specifically when the script is processing few transactions sequentially):

FIREBLOCKS_API_KEY=12345678-1234-1234-1234-123456789abc \ 
FIREBLOCKS_API_PRIVATE_KEY_PATH=/path/to/secret.key \ 
fireblocks-json-rpc --http -- \ 
forge script script/Hello.s.sol:MyScript \
--sender <sender_address> --slow --broadcast --unlocked --rpc-url {} 
  • sender_address can be found in your Fireblocks workspace, through Fireblocks API, or using the JSON RPC directly.
    Get address of vault account 0:
FIREBLOCKS_API_KEY=12345678-1234-1234-1234-123456789abc \ 
FIREBLOCKS_API_PRIVATE_KEY_PATH=/path/to/secret.key \ 
fireblocks-json-rpc --http --vaultAccountIds 0 -- curl {} \
  -X POST \
  -H "Content-Type: application/json" \
  --data '{"method":"eth_accounts","id":1,"jsonrpc":"2.0"}'

This should take a couple of minutes to run if everything was configured correctly.