Lint your Solidity contracts with Ethlint

Ethlint (Formerly Solium) analyzes your Solidity code for style & security issues and fixes them.


npm install -g ethlint
solium -V

For backward-compatibility, you can still use npm install -g solium.

If you're currently using the solium package for npm install, it is highly recommended that you move to ethlint. The solium package will not receive updates after December, 2019. There are no differences between the updates pushed to ethlint and solium packages.


In the root directory of your DApp:

solium --init

This creates 2 files for you: - .soliumignore - contains names of files and directories to ignore while linting - .soliumrc.json - contains configuration that tells Solium how to lint your project. You should modify this file to configure rules, plugins and sharable configs.

.soliumrc.json looks like:

  "extends": "solium:recommended",
  "plugins": ["security"],
  "rules": {
    "quotes": ["error", "double"],
    "indentation": ["error", 4],
    "linebreak-style": ["error", "unix"]

To know which lint rules Solium applies for you, see Style rules and Security rules.


Solium does not strictly adhere to the Solidity Style Guide. It aims to promote coding practices agreed upon by the community at large.


solium -f foobar.sol
solium -d contracts/

Configure with comments

Comment Directives can be used to configure Solium to ignore specific pieces of code. They follow the pattern solium-disable<optional suffix>.

If you only use the directive, Solium disables all rules for the marked code. If that's not desirable, specify the rules to disable after the directive, separated by comma.

contract Foo {
    /* solium-disable-next-line */
    function() {
        bytes32 bar = 'Hello world';    // solium-disable-line quotes

        // solium-disable-next-line security/no-throw, indentation
/* solium-disable */

contract Foo {


Solium automatically fixes your code to resolve whatever issues it can.

solium -d contracts/ --fix

Next steps