JSON Validator & Repair
Diagnose and fix corrupted JSON with detailed error reports.
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What is JSON Validation?
JSON validation is the process of checking whether a JSON string conforms to the JSON specification. A valid JSON document must follow strict syntax rules: keys must be double-quoted, strings must use double quotes, trailing commas are not allowed, and brackets must be properly balanced.
This tool goes beyond basic validation by also offering automatic repair of common JSON issues. If your JSON has missing quotes, trailing commas, single quotes, or other problems, the repair engine can fix them automatically.
Common issues that can be fixed:
- Missing quotes around keys and string values
- Trailing or missing commas
- Single quotes instead of double quotes
- Missing escape characters in strings
- Unbalanced brackets and braces
- Truncated JSON (incomplete documents)
- Comments (JSONC format)
How to Use
- Paste your JSON — Copy and paste any JSON data (valid or corrupted) into the input textarea. You can also click Corrupted Example to load a sample.
- Validate — Click Validate to check for syntax errors. The tool reports the exact line number and column position of each issue.
- Repair — Click Repair to automatically fix common JSON issues. The repaired JSON appears in the output area.
- Format — Click Format to beautify the input JSON with proper indentation.
- Copy or download — Use the copy button on the output area or click Download .json to save the result as a file.
Frequently Asked Questions
What is the difference between JSON Validator and JSON Formatter?
The JSON Validator focuses on diagnosing and repairing corrupted JSON. It finds ALL syntax errors with detailed line/column information and can automatically fix common issues. The JSON Formatter focuses on beautifying and minifying valid JSON. Use the Validator when your JSON has errors, use the Formatter when you need to clean up or compress valid JSON.
What types of JSON errors can be repaired?
The repair engine can handle: missing quotes around keys or string values, trailing commas, missing commas between elements, single quotes instead of double quotes, unescaped control characters in strings, unbalanced brackets, truncated JSON, Python-style literals (None, True, False), JavaScript comments (// and /* */), and more.
Is this tool safe for sensitive data?
Yes. All processing happens entirely in your browser using JavaScript. Your JSON data is never uploaded to any server, stored in any database, or logged. This makes it safe for debugging sensitive configuration files or API responses containing private information.
