✅ JSON Validator — Validate & Check JSON Syntax Instantly
Instantly check if your JSON is valid. Get exact error location and line numbers — all in your browser. Free & private.
Paste JSON objects, arrays, or any valid JSON string for instant validation.
How to Use the JSON Validator
- Paste Your JSON — Copy your JSON from an API response, config file, or any source and paste it into the input area.
- Click Validate JSON — The tool parses your input and checks the syntax immediately.
- Read the Results — A green badge confirms valid JSON; a red badge shows the exact error message.
- Fix and Re-validate — Correct any errors shown in the input area and click Validate again.
- Inspect the Tree — For valid JSON, expand the syntax-highlighted tree to verify structure and data types.
Key Features
🔍
Exact Error Location
Shows the precise syntax error message.
✅
Instant Validation
Validates using browser's native JSON parser.
🌲
Tree Preview
Syntax-highlighted tree for easy inspection.
⚠️
Duplicate Key Warning
Detects duplicate keys that cause data loss.
🔒
100% Client-Side
Your JSON never leaves your browser.
📊
JSON Stats
Size, key count, nesting depth.
Frequently Asked Questions
Is this tool free to use?
Yes, completely free with no registration required.
Does the validator show where the error is?
Yes, including the exact error message from the JSON parser.
Is my data safe?
Yes. All validation runs in your browser. No data is ever transmitted to a server.
Why does my JSON fail validation?
Common reasons: trailing commas, single quotes instead of double quotes, unquoted keys.
Can I validate JSON arrays?
Yes, the validator handles objects, arrays, nested structures, and primitive values.