JSON Validator
Check whether your JSON is valid and get the exact line, column and reason for any error. One click repairs common mistakes like trailing commas, single quotes and comments.
Runs in your browser — nothing is uploaded Free, no limits
JSON input
Tree view
How to use the JSON Validator
- Paste your JSON or open a .json file.
- Read the result: a green "Valid JSON" or the error's line, column and a highlighted snippet.
- Click Try auto-fix to repair trailing commas, single quotes, unquoted keys and comments.
- Review the fixed JSON, then copy or download the formatted result.
Frequently asked questions
What are the most common JSON errors?
Trailing commas after the last item, single quotes instead of double quotes, property names without quotes, comments, and missing commas between values. JSON is stricter than JavaScript object syntax and allows none of these.
Why does the error point at a different line than my mistake?
A parser reports where it first notices something is wrong. A missing comma or quote is usually detected at the start of the next value, so check the line shown and the end of the line just above it.
Are comments allowed in JSON?
No. Standard JSON (RFC 8259) has no comment syntax. Some tools accept JSONC or JSON5, which allow comments, but a strict parser such as JSON.parse will reject them. Auto-fix removes // and /* */ comments.
Is auto-fix safe?
It only touches syntax — it removes comments and trailing commas, converts single quotes to double quotes, quotes bare property names and replaces Python-style True/False/None. It's applied only when you click the button and lists every change so you can review it.
Does valid JSON mean my data is correct?
Valid JSON only means the syntax is correct. To check that required fields exist and have the right types, you also need a JSON Schema validator for your specific data format.
Is my data uploaded anywhere?
No. Validation runs entirely in your browser with no network requests, so it's safe for private API responses and configuration files.