JSON Validator
Validate JSON online for free. Get a clear error message with line and column when something's wrong — nothing uploaded to a server.
Your files are processed locally in your browser and are not uploaded to our servers.
How to use JSON Validator
- 1
Paste your JSON into the box.
- 2
Click "Validate JSON."
- 3
If it's invalid, the error message includes the line and column where parsing failed, when the browser's JSON parser reports one.
- 4
If it's valid, jump straight to the Formatter to pretty-print it.
Common uses
- Checking hand-written JSON (a config file, a test fixture) before using it
- Finding the exact spot a large API response or config file broke
- A quick sanity check before pasting JSON into a strict system that will reject anything malformed
Supported formats and limitations
Accepts JSON, up to one file at a time.
- Line and column are shown when the browser's JSON parser reports a position for the error — not every parse error includes one, in which case only the error message is shown.
- This checks JSON syntax only — it doesn't validate against a JSON Schema or check that specific fields exist.
Frequently asked questions
No. Validation happens entirely in your browser using the native JSON parser.
Usually, but not always — it depends on whether the browser's own JSON parser reports a position for that specific error. When it doesn't, you still get the error message itself.
No — this checks that the JSON is syntactically valid, not that it matches a particular structure or set of required fields.
Use the "Format this JSON" shortcut to jump straight to the JSON Formatter and pretty-print it.