JSON Validator instantly checks whether your JSON string is syntactically valid, pinpointing the exact line and character where an error occurs. Unlike a formatter, it focuses purely on correctness — no reformatting, no data transformation. Paste minified API responses, configuration files, or hand-written JSON and get a clear pass or fail result in milliseconds, entirely in your browser.
How it Works
1Paste or type your JSON into the input field.
2The validator parses the text using the browser's native JSON.parse engine.
3If valid, a green confirmation is shown. If invalid, the exact error position and message are highlighted.
4Fix the reported error and re-validate until the input is clean.
Frequently Asked Questions
What is the difference between JSON validation and JSON formatting?
Validation checks whether the JSON is syntactically correct — proper quoting, no trailing commas, matching brackets, etc. Formatting (pretty-printing) changes the indentation and whitespace for readability. You can validate without formatting and format without validating; this tool focuses solely on correctness.
Why does my JSON fail validation when it looks correct?
The most common culprits are: trailing commas after the last property or array element (not allowed in JSON), single quotes instead of double quotes around strings or keys, JavaScript comments (// or /* */), and unescaped control characters inside strings. The error message points to the exact position of the issue.
Does this tool send my data to a server?
No. Validation runs entirely in your browser using JavaScript's built-in JSON.parse. Your data never leaves your device, making it safe for sensitive payloads like API keys or private configuration.
Can I validate JSON arrays as well as objects?
Yes. JSON arrays (starting with [) are fully valid top-level JSON values, and the validator accepts them alongside objects ({...}), strings, numbers, booleans, and null.