JavaScript Validator
Use this free online JavaScript Validator to check JavaScript code for syntax errors. It works instantly in your browser, and your data never leaves your device.
About the JavaScript Validator
The validator parses your script with a modern ES2023 parser and reports syntax errors with line and column numbers before you deploy.
Also known as: javascript syntax checker, js lint.
How to use the JavaScript Validator
- Paste your input into the box above, upload a file, or click Sample to try an example.
- Pick any options you need. The JavaScript Validator processes your input instantly as you type.
- Click Copy to copy the output or Download to save it as a file.
Features
- Free with no signup and no daily limits
- Private: runs entirely in your browser
- Works on mobile, tablet and desktop
- Upload files and download results
- Live results as you type, with clear error messages
- Clean, fast interface with no popups
Frequently asked questions
Is the JavaScript Validator free to use?
Yes. The JavaScript Validator is completely free with no signup, no limits on normal use and no watermark.
Is my data safe?
Yes. Everything is processed by JavaScript inside your own browser. Your text is never uploaded to our server or stored anywhere.
Can I choose the indentation?
Yes. Pick 2 spaces, 4 spaces or tabs from the options, and the output updates instantly.
Does it work offline and on mobile?
Once the page has loaded, the tool runs in your browser and works on phones, tablets and desktops.
What else is this tool called?
People also search for it as javascript syntax checker, js lint. It is the same free tool.