Code Linters and Formatters for Web Developers

Warning: This list is no longer maintained, and some links may no longer work.

Official online version of popular projects that improve your JavaScript code

Prettier (formatter)

https://prettier.io/playground/

ESLint (linter)

https://eslint.org/play/

JSHint (linter)

https://jshint.com/

Tools for other languages

CSS

• https://www.codebeautifier.com/

HTML

• https://prettier.io/playground/, pick the html parser

JSON

• https://jsonformatter.curiousconcept.com/
• https://jsonformatter.org/

GraphQL

• https://prettier.io/playground/, pick the graphql parser

General purpose (handle more than 1 single syntax)

The Prettier playground also formats HTML, CSS, GraphQL, Markdown and YAML. You pick the parser in the sidebar.

Want me to talk about your product? You can sponsor this site.