eslint vs standard vs xo vs semistandard

JavaScript Code Linting and Style Enforcement Tools

eslint, semistandard, standard, and xo are all tools designed to enforce code quality and consistency in JavaScript projects by identifying problematic patterns, stylistic issues, and potential bugs. eslint is a highly configurable linter that serves as the foundation for many style guides. standard, semistandard, and xo are opinionated wrappers built on top of eslint that provide predefined rule sets with minimal or zero configuration required. While standard enforces a strict no-semicolons style, semistandard allows semicolons but otherwise follows standard's conventions. xo offers a modern, slightly more flexible alternative with sensible defaults focused on ES2020+ features and common best practices.

Package	Downloads	Stars	Size	Issues	Publish	License

eslint	80,325,944	26,901	2.89 MB	95	10 days ago	MIT
standard	532,321	29,428	164 kB	128	a year ago	MIT
xo	285,747	7,950	84.6 kB	64	4 months ago	MIT
semistandard	20,702	1,417	47.6 kB	0	3 years ago	MIT

JavaScript Linting Showdown: ESLint vs Standard vs Semistandard vs XO

Choosing a JavaScript linter isn't just about catching bugs — it's about defining how your team writes code every day. The four tools here represent different philosophies: from total configurability (eslint) to rigid convention (standard), with pragmatic middle grounds in between. Let's break down how they actually work in practice.

⚙️ Configuration Philosophy: Zero-Config vs Full Control

eslint starts with no rules enabled by default. You must explicitly configure everything.

// .eslintrc.js
module.exports = {
  env: { es2021: true, node: true },
  extends: ['eslint:recommended'],
  rules: {
    'no-console': 'warn',
    'indent': ['error', 2],
    'quotes': ['error', 'single']
  }
};

standard provides zero configuration. No config file needed — just install and run.

# No .eslintrc, no config
npx standard

semistandard also offers zero configuration, but differs from standard only in semicolon handling.

# Same zero-config approach
npx semistandard

xo uses sensible defaults with optional overrides. Most projects need no config, but you can customize via package.json.

// package.json
{
  "xo": {
    "semicolon": false,
    "space": true
  }
}

📏 Code Style Rules: Semicolons, Quotes, and Indentation

Here's how each tool handles basic formatting:

// Input code
function greet(name) {
  return "Hello, " + name
}

const message = greet('World')
console.log(message)

eslint (with recommended config) won't flag any of this — you'd need to enable specific style rules.

standard will complain about missing semicolons and double quotes:

# standard output
  2:30  error  Strings must use single quotes
  2:39  error  Missing semicolon
  5:30  error  Missing semicolon

semistandard only complains about the quotes (allows semicolons):

# semistandard output
  2:30  error  Strings must use single quotes

xo by default requires semicolons and single quotes:

# xo output
  2:30  error  Strings must use single quotes
  2:39  error  Missing semicolon
  5:30  error  Missing semicolon

🔌 Extensibility and Plugin Ecosystem

eslint has the richest ecosystem. You can extend configs, write custom rules, and integrate with frameworks:

// Using popular configs and plugins
module.exports = {
  extends: [
    'eslint:recommended',
    'plugin:react/recommended',
    '@typescript-eslint/recommended'
  ],
  plugins: ['react', '@typescript-eslint']
};

standard, semistandard, and xo all build on eslint internally but limit customization:

standard/semistandard: Can add global variables only via CLI flags or comments
```
/* eslint-env browser */
/* global myGlobal */
```

xo: Supports some config overrides and ignores, plus limited plugin support:

{
  "xo": {
    "extends": ["plugin:react/recommended"],
    "plugins": ["react"]
  }
}

🧪 Modern JavaScript and TypeScript Support

eslint supports everything through parsers and plugins:

// For TypeScript
module.exports = {
  parser: '@typescript-eslint/parser',
  plugins: ['@typescript-eslint']
};

standard and semistandard only support JavaScript (ES2020+). No TypeScript support.

xo supports TypeScript with additional setup:

npm install --save-dev typescript @typescript-eslint/parser @typescript-eslint/eslint-plugin

Then configure in package.json:

{
  "xo": {
    "parser": "@typescript-eslint/parser",
    "plugins": ["@typescript-eslint"]
  }
}

🛠️ Fixing Issues Automatically

All four tools support automatic fixing, but with different workflows:

eslint:

npx eslint --fix src/

standard:

npx standard --fix

semistandard:

npx semistandard --fix

xo:

npx xo --fix

However, standard and semistandard have more limited auto-fix capabilities compared to eslint and xo, especially for complex stylistic issues.

🎯 Real-World Decision Scenarios

Scenario 1: Enterprise Application with Strict Requirements

You're building a large application with multiple teams, custom coding standards, and framework-specific rules.

✅ Best choice: eslint
Why? Full control over rules, ability to create shareable configs, and extensive plugin ecosystem.

Scenario 2: Open Source Library with Minimal Overhead

You're publishing a small utility library and want contributors to follow consistent style without configuration debates.

✅ Best choice: standard or semistandard
Why? Zero-config means contributors can start immediately; choose based on semicolon preference.

Scenario 3: Modern React App with TypeScript

You're building a new React application using TypeScript and hooks, wanting modern defaults with room for minor adjustments.

✅ Best choice: xo
Why? Built-in support for modern JS/TS features, sensible React defaults, and easy overrides.

Scenario 4: Legacy Codebase Migration

You're gradually introducing linting to a large existing codebase with inconsistent style.

✅ Best choice: eslint
Why? Ability to start with minimal rules and gradually increase strictness using overrides for different file types or directories.

📊 Summary Table

Feature	`eslint`	`standard`	`semistandard`	`xo`
Configuration	Full control	Zero config	Zero config	Minimal config
Semicolons	Configurable	Forbidden	Required	Required (configurable)
Extensibility	Unlimited	Very limited	Very limited	Moderate
TypeScript	Yes (with plugins)	No	No	Yes (with setup)
Auto-fix	Comprehensive	Basic	Basic	Good
Learning Curve	Steep	None	None	Low

💡 Final Recommendation

Need maximum flexibility? Go with eslint — it's the industry standard for a reason.
Want to eliminate style debates entirely? Choose standard (no semicolons) or semistandard (with semicolons).
Building modern apps with some customization needs? xo gives you the best balance of opinionated defaults and escape hatches.

Remember: the best linter is the one your team actually uses consistently. Don't let perfect be the enemy of good — even basic linting catches real bugs and prevents style arguments that waste valuable development time.

eslint:
Choose eslint when you need full control over your linting rules, custom configurations, or integration with complex project requirements. It's ideal for large teams or organizations that require tailored coding standards, support for multiple environments (browser, Node.js, etc.), or gradual adoption of linting rules through overrides and plugins.
standard:
Choose standard when you want a completely zero-configuration linter that enforces a consistent style without any decision-making overhead. It's well-suited for small to medium projects where team members agree to adopt its opinionated rules, including no semicolons, 2-space indentation, and single quotes, allowing everyone to focus on logic rather than formatting debates.
xo:
Choose xo if you prefer a modern, slightly more flexible opinionated linter that supports the latest JavaScript features out of the box while still requiring minimal configuration. It's ideal for new projects using ES2020+ syntax, TypeScript (with additional setup), and developers who want sensible defaults with easy overrides for specific rules without abandoning the zero-config philosophy entirely.
semistandard:
Choose semistandard if your team prefers using semicolons in JavaScript but still wants the simplicity and zero-configuration benefits of the standard style guide. It's a good middle ground for developers who find standard's no-semicolon rule too restrictive but appreciate its other conventions around spacing, naming, and code structure.

eslint

standard

xo

semistandard

ESLint

Website | Configure ESLint | Rules | Contribute to ESLint | Report Bugs | Code of Conduct | X | Discord | Mastodon | Bluesky

ESLint is a tool for identifying and reporting on patterns found in ECMAScript/JavaScript code. In many ways, it is similar to JSLint and JSHint with a few exceptions:

ESLint uses Espree for JavaScript parsing.
ESLint uses an AST to evaluate patterns in code.
ESLint is completely pluggable, every single rule is a plugin and you can add more at runtime.

Table of Contents

Installation and Usage

Prerequisites: Node.js (^20.19.0, ^22.13.0, or >=24) built with SSL support. (If you are using an official Node.js distribution, SSL is always built in.)

You can install and configure ESLint using this command:

npm init @eslint/config@latest

After that, you can run ESLint on any file or directory like this:

npx eslint yourfile.js

pnpm Installation

To use ESLint with pnpm, we recommend setting up a .npmrc file with at least the following settings:

auto-install-peers=true
node-linker=hoisted

This ensures that pnpm installs dependencies in a way that is more compatible with npm and is less likely to produce errors.

Configuration

You can configure rules in your eslint.config.js files as in this example:

import { defineConfig } from "eslint/config";

export default defineConfig([
	{
		files: ["**/*.js", "**/*.cjs", "**/*.mjs"],
		rules: {
			"prefer-const": "warn",
			"no-constant-binary-expression": "error",
		},
	},
]);

The names "prefer-const" and "no-constant-binary-expression" are the names of rules in ESLint. The first value is the error level of the rule and can be one of these values:

"off" or 0 - turn the rule off
"warn" or 1 - turn the rule on as a warning (doesn't affect exit code)
"error" or 2 - turn the rule on as an error (exit code will be 1)

The three error levels allow you fine-grained control over how ESLint applies rules (for more configuration options and details, see the configuration docs).

Version Support

The ESLint team provides ongoing support for the current version and six months of limited support for the previous version. Limited support includes critical bug fixes, security issues, and compatibility issues only.

ESLint offers commercial support for both current and previous versions through our partners, Tidelift and HeroDevs.

See Version Support for more details.

Code of Conduct

ESLint adheres to the OpenJS Foundation Code of Conduct.

Filing Issues

Before filing an issue, please be sure to read the guidelines for what you're reporting:

Frequently Asked Questions

Does ESLint support JSX?

Yes, ESLint natively supports parsing JSX syntax (this must be enabled in configuration). Please note that supporting JSX syntax is not the same as supporting React. React applies specific semantics to JSX syntax that ESLint doesn't recognize. We recommend using eslint-plugin-react if you are using React and want React semantics.

Does Prettier replace ESLint?

No, ESLint and Prettier have different jobs: ESLint is a linter (looking for problematic patterns) and Prettier is a code formatter. Using both tools is common, refer to Prettier's documentation to learn how to configure them to work well with each other.

What ECMAScript versions does ESLint support?

ESLint has full support for ECMAScript 3, 5, and every year from 2015 up until the most recent stage 4 specification (the default). You can set your desired ECMAScript syntax and other settings (like global variables) through configuration.

What about experimental features?

ESLint's parser only officially supports the latest final ECMAScript standard. We will make changes to core rules in order to avoid crashes on stage 3 ECMAScript syntax proposals (as long as they are implemented using the correct experimental ESTree syntax). We may make changes to core rules to better work with language extensions (such as JSX, Flow, and TypeScript) on a case-by-case basis.

In other cases (including if rules need to warn on more or fewer cases due to new syntax, rather than just not crashing), we recommend you use other parsers and/or rule plugins. If you are using Babel, you can use @babel/eslint-parser and @babel/eslint-plugin to use any option available in Babel.

Once a language feature has been adopted into the ECMAScript standard (stage 4 according to the TC39 process), we will accept issues and pull requests related to the new feature, subject to our contributing guidelines. Until then, please use the appropriate parser and plugin(s) for your experimental feature.

Which Node.js versions does ESLint support?

ESLint updates the supported Node.js versions with each major release of ESLint. At that time, ESLint's supported Node.js versions are updated to be:

The most recent maintenance release of Node.js
The lowest minor version of the Node.js LTS release that includes the features the ESLint team wants to use.
The Node.js Current release

ESLint is also expected to work with Node.js versions released after the Node.js Current release.

Refer to the Quick Start Guide for the officially supported Node.js versions for a given ESLint release.

Where to ask for help?

Open a discussion or stop by our Discord server.

Why doesn't ESLint lock dependency versions?

Lock files like package-lock.json are helpful for deployed applications. They ensure that dependencies are consistent between environments and across deployments.

Packages like eslint that get published to the npm registry do not include lock files. npm install eslint as a user will respect version constraints in ESLint's package.json. ESLint and its dependencies will be included in the user's lock file if one exists, but ESLint's own lock file would not be used.

We intentionally don't lock dependency versions so that we have the latest compatible dependency versions in development and CI that our users get when installing ESLint in a project.

The Twilio blog has a deeper dive to learn more.

Releases

We have scheduled releases every two weeks on Friday or Saturday. You can follow a release issue for updates about the scheduling of any particular release.

Security Policy

ESLint takes security seriously. We work hard to ensure that ESLint is safe for everyone and that security issues are addressed quickly and responsibly. Read the full security policy.

Semantic Versioning Policy

ESLint follows semantic versioning. However, due to the nature of ESLint as a code quality tool, it's not always clear when a minor or major version bump occurs. To help clarify this for everyone, we've defined the following semantic versioning policy for ESLint:

Patch release (intended to not break your lint build)
- A bug fix in a rule that results in ESLint reporting fewer linting errors.
- A bug fix to the CLI or core (including formatters).
- Improvements to documentation.
- Non-user-facing changes such as refactoring code, adding, deleting, or modifying tests, and increasing test coverage.
- Re-releasing after a failed release (i.e., publishing a release that doesn't work for anyone).
Minor release (might break your lint build)
- A bug fix in a rule that results in ESLint reporting more linting errors.
- A new rule is created.
- A new option to an existing rule that does not result in ESLint reporting more linting errors by default.
- A new addition to an existing rule to support a newly-added language feature (within the last 12 months) that will result in ESLint reporting more linting errors by default.
- An existing rule is deprecated.
- A new CLI capability is created.
- New capabilities to the public API are added (new classes, new methods, new arguments to existing methods, etc.).
- A new formatter is created.
- eslint:recommended is updated and will result in strictly fewer linting errors (e.g., rule removals).
Major release (likely to break your lint build)
- eslint:recommended is updated and may result in new linting errors (e.g., rule additions, most rule option updates).
- A new option to an existing rule that results in ESLint reporting more linting errors by default.
- An existing formatter is removed.
- Part of the public API is removed or changed in an incompatible way. The public API includes:
  - Rule schemas
  - Configuration schema
  - Command-line options
  - Node.js API
  - Rule, formatter, parser, plugin APIs

According to our policy, any minor update may report more linting errors than the previous release (ex: from a bug fix). As such, we recommend using the tilde (~) in package.json e.g. "eslint": "~3.1.0" to guarantee the results of your builds.

ESM Dependencies

Since ESLint is a CommonJS package, there are restrictions on which ESM-only packages can be used as dependencies.

Packages that are controlled by the ESLint team and have no external dependencies can be safely loaded synchronously using require(esm) and therefore used in any contexts.

For external packages, we don't use require(esm) because a package could add a top-level await and thus break ESLint. We can use an external ESM-only package only in case it is needed only in asynchronous code, in which case it can be loaded using dynamic import().

License

MIT License

Copyright OpenJS Foundation and other contributors, <www.openjsf.org>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Team

These folks keep the project moving and are resources for help.

Technical Steering Committee (TSC)

The people who manage releases, review feature requests, and meet regularly to ensure ESLint is properly maintained.

Nicholas C. Zakas

Francesco Trotta

Milos Djermanovic

Reviewers

The people who review and implement new features.

唯然	Nitin Kumar

Committers

The people who review and fix bugs and help triage issues.

Josh Goldberg ✨

Website Team

Team members who focus specifically on eslint.org

Sponsors

The following companies, organizations, and individuals support ESLint's ongoing maintenance and development. Become a Sponsor to get your logo on our READMEs and website.

Platinum Sponsors

Gold Sponsors

Silver Sponsors

Bronze Sponsors

Technology Sponsors

Technology sponsors allow us to use their products and services for free as part of a contribution to the open source ecosystem and our work.