solcjs

Compile Solidity smart contracts to bytecode

TLDR

Compile a specific contract to hex

$ solcjs --bin [path/to/file.sol]

Compile the ABI of a specific contract

$ solcjs --abi [path/to/file.sol]

Specify a base path to resolve imports from

$ solcjs --bin --base-path [path/to/directory] [path/to/file.sol]

Specify one or more paths to include containing external code

$ solcjs --bin --include-path [path/to/directory] [path/to/file.sol]

Optimise the generated bytecode

$ solcjs --bin --optimize [path/to/file.sol]

SYNOPSIS

solcjs [options] file...
solcjs --standard-json
solcjs --help
solcjs --version

--version
    Displays the current version of the solcjs compiler.

--optimize
    Enables the bytecode optimizer, which attempts to reduce transaction costs and contract size.

--bin
    Outputs the compiled contract bytecode in hexadecimal format.

--abi
    Outputs the Application Binary Interface (ABI) for compiled contracts, essential for contract interaction.

--output-dir

    Specifies a directory where all compilation output files should be written.

--base-path
    Sets the base path for resolving imports, often used for project root directories.

--include-path
    Adds an additional path for resolving imports, useful for library dependencies.

--standard-json
    Instructs solcjs to accept a Standard JSON Input object from stdin and print a Standard JSON Output object to stdout. This is the recommended interface for programmatic use.

--pretty-json
    Formats JSON output with indentation, making it more human-readable.

--help
    Displays a help message with available options and usage information.

DESCRIPTION

solcjs is the command-line interface for the JavaScript implementation of the Solidity compiler. It enables developers to compile Solidity smart contracts directly from the command line, generating bytecode, ABI (Application Binary Interface), and other artifacts necessary for deploying and interacting with contracts on Ethereum-compatible blockchains. Being Node.js-based, solcjs is easily integrated into JavaScript development environments, build scripts, and CI/CD pipelines, offering a flexible alternative or complement to the C++-based solc compiler. It supports various compilation settings, including optimization, import path resolution, and detailed output selection, making it a crucial tool in modern blockchain development workflows.

CAVEATS

solcjs requires Node.js to be installed and available in the system's PATH. Complex projects with multiple source files and intricate import structures often benefit more from using the Standard JSON Input interface rather than direct file paths and `--include-path`/`--base-path` options, as it provides more robust import resolution and error reporting. Performance characteristics might differ slightly from the C++ solc compiler.

STANDARD JSON INPUT/OUTPUT

For advanced and programmatic use, solcjs strongly recommends using the Standard JSON Input format. This allows developers to pass a comprehensive JSON object containing all source files, compiler settings, and output selections, receiving a structured JSON output. This method ensures robust and reproducible compilation across different environments and is the backbone of most high-level Solidity development frameworks.

INTEGRATION WITH DEVELOPMENT FRAMEWORKS

Popular Ethereum development frameworks such as Truffle, Hardhat, and Brownie (via their underlying JS components) frequently utilize solcjs (or the solc-js npm package) behind the scenes for compiling smart contracts. These frameworks abstract away the complexities of direct solcjs command-line invocation, providing a streamlined development experience while leveraging the compiler's capabilities.

HISTORY

solcjs originated as the Node.js binding for the core Solidity compiler, aiming to provide a JavaScript-native interface to the powerful solc compilation engine. Its development was driven by the rapid growth of the Ethereum ecosystem and the increasing adoption of JavaScript/Node.js for decentralized application (dApp) development and blockchain tooling. By offering a familiar environment for compilation, solcjs significantly eased integration into existing web development workflows, build tools, and frameworks like Truffle and Hardhat, making Solidity contract compilation more accessible to a broader developer community primarily working with Node.js.