Free online JavaScript linter
Lint JavaScript online for free. Check syntax and common issues privately in your browser - a quick paste-and-check helper, not a full ESLint replacement. Nothing uploaded.
What you can do
Syntax checks
Parse JavaScript online and surface syntax errors with line and column when available.
Common warnings
Catch lightweight issues like loose equality, var, and eval - not a full ESLint suite.
Private by default
Lint JavaScript online for free in your browser. Nothing is uploaded.
How to lint JavaScript online
- Paste your JavaScript (or click Sample).
- Run Lint to parse and scan for common issues locally.
- Fix reported errors and warnings, then lint again.
- Beautify with the free online JS Beautifier or compress with the JS Minifier.
Frequently asked questions
Learn more
Related tools: JS Beautifier, JS Minifier, Regex tester.
Why lint JavaScript online locally?
A free online JavaScript linter shortens the loop when you paste a snippet and need a quick syntax check before beautify or minify. Running privately in the browser keeps source on your device - use ESLint in your repo for full project rules.