# Build File Format

bw uses the same format for built smart contracts as Truffle (opens new window). However, you need not use Truffle itself, but the format was chosen to avoid creating many different standards.

Here's what this format looks like:

    "abi": [
            "constant": true,
            "inputs": [],
            "name": "name",
            "outputs": [
                    "name": "",
                    "type": "string"
            "payable": false,
            "stateMutability": "view",
            "type": "function"
    "bytecode": "0x..."

It's simply a JSON file with an object that has at least these two keys:

  • abi The ABI for the contract.
  • bytecode The bytecode for deploying the contract.

With this file, you can both deploy and interact with contracts. It can be used with the --abi option as well as with contract-deploy.

# Creating a build file

If you don't use Truffle, you can create a build file easily using the jo tool (opens new window) from solc output.

If you use solc with the following command:

solc --bin --abi -o build contracts/MyContract.sol

You can create the JSON build file using the following jo command:

jo abi:=build/MyContract.abi bytecode=0x$(cat build/MyContract.bin) > build/MyContract.json

Then the build file will be in build/MyContract.json.