What errors can the JSON validator detect?

It detects common JSON syntax errors: missing quotes, trailing commas, mismatched brackets, unquoted property names, single-quoted strings, comments, and invalid value types. Error messages include line number, column, and specific reason for quick debugging.

How large a JSON file can I validate?

As a pure front-end tool, it's limited by browser memory. Generally supports JSON up to ~10MB. For very large JSON files, the browser may briefly lag. For extremely large JSON, consider using command-line tools like jq.

Is my data sent to a server?

No. All JSON parsing and validation runs in your browser locally. Your data never leaves your device. You can safely use sensitive JSON configs containing API keys or user data — complete privacy.

Free Online JSON Validator & Formatter - Validate, Beautify, Minify

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Updated: 2026-07-12

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Input JSON

🌲 JSON Tree View

Validate JSON to browse structure here

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📖 How to Use

1. Paste JSON: Paste your JSON code in the left input box. Auto-validation runs as you type.

2. Validate & Fix: Syntax errors show exact line/column. Click "Beautify" to format JSON.

3. Browse Structure: The right tree view displays JSON structure. Click arrows to expand/collapse nodes.

❓ FAQ

What errors can it detect?

Detects common JSON errors: missing quotes, trailing commas, mismatched brackets, unquoted keys, single quotes, comments, and invalid values. Shows exact line number, column, and specific error reason.

How large a JSON can I validate?

Pure front-end, limited by browser memory. Typically supports JSON up to ~10MB. Large JSON may cause brief lag. For extremely large files, use command-line tools like jq.

Is my data sent anywhere?

No. All parsing and validation runs locally in your browser. Your data never leaves your device. Safe for sensitive JSON with API keys or user data — complete privacy.

📋 JSON Validator & Formatter