JSON Validator
Validate your JSON live as you type — the status updates instantly and errors are underlined on the exact line.
JSON to validate
Formatted output
No output yet
Valid JSON is formatted here as you type.
About the JSON Validator
A JSON validator checks that your text is well-formed JSON and pinpoints the first place it breaks. Instead of a vague 'invalid JSON' from your app, you get the exact line and character where the parser fails.
This validator lints as you type, underlining problems inline the moment they appear. It runs in your browser with the native JSON parser, so a passing document is guaranteed to parse anywhere else that follows the JSON spec.
How to use the JSON Validator
- 1Paste your JSON into the editor, or load a sample to see how errors are reported.
- 2Watch the gutter and underline markers — the exact position of any syntax error is flagged live.
- 3Fix the highlighted issue (a common one is a trailing comma or a missing quote).
- 4Once valid, copy the cleaned, formatted output from the result pane.
Common uses
Catching syntax errors
Find the exact comma or bracket breaking a config file or API payload.
Verifying pasted data
Confirm JSON copied from logs or docs is intact before using it in code.
Teaching JSON
See in real time why a snippet is or isn't valid JSON.
Frequently asked questions
What counts as valid JSON?
Valid JSON uses double-quoted keys and strings, no trailing commas, no comments, and only the types string, number, boolean, null, array, and object. JSON5 and JavaScript object literals are more permissive and are not valid JSON.
Why is my JSON with comments invalid?
The JSON specification does not allow comments. If your file needs comments (like tsconfig.json), your tooling uses JSONC, a superset — but standard JSON parsers will reject it.
Does the validator check against a schema?
This tool validates syntax and structure. To generate or check against a JSON Schema, use the JSON Schema Generator.
Is my data private?
Yes. Validation runs entirely in your browser; nothing is transmitted or stored.