Online Tool Store
JSON Validator
Validate JSON as you type, with clear line-and-column error hints, plus one-click pretty-printing and minifying, entirely in your browser.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Example shown — this one has a deliberate trailing comma so you can see an error reported.
How the JSON validator works
- Paste or type JSON into the box above.
- The tool validates it instantly as you type, showing a clear valid/invalid status.
- If it's invalid, the exact line and column of the problem is shown so you can fix it quickly; if it's valid, use Pretty-print or Minify to reformat it.
FAQ
Why doesn’t my JSON with a trailing comma work?
Standard JSON doesn’t allow a trailing comma after the last item in an object or array — that’s different from JavaScript object literals, which do allow it. This is the single most common reason "valid-looking" JSON fails to parse.
Does it point to exactly where the error is?
Yes, when the browser’s JSON parser reports a character position — the validator converts that position into a line and column number so you can jump straight to the problem.
What’s the difference between Pretty-print and Minify?
Pretty-print reformats valid JSON with 2-space indentation for readability; Minify strips all unnecessary whitespace to produce the smallest possible output, useful before pasting JSON into a config file or API payload.
Is my JSON uploaded anywhere?
No. Validation uses your browser’s built-in JSON.parse — nothing is sent to Online Tool Store or any other server.
How we compare
| Feature | Online Tool Store | JSONLint | Browser DevTools console |
|---|---|---|---|
| Validates as you type, no button | ✓ | Validate button | Manual JSON.parse call |
| Pretty-print and minify built in | ✓ | ✓ | Requires extra code |
| No ads or sign-up | ✓ | Ad-supported | ✓ |
For a fast, live-updating JSON check with clear line-level error hints, the Online Tool Store JSON Validator saves the round trip through a linting button.