JSON Validator

Free online JSON Validator. Locate syntax errors, identify character position issues, find missing commas/quotes, and validate JSON payloads instantly. 100% private in-browser.

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How to Use JSON Validator

  1. Type or paste your raw JSON string into the input text area.
  2. Click "Validate JSON" to verify RFC 8259 syntax conformity.
  3. If invalid, review the exact line number, column index, and character that triggered the parser exception.
  4. Use the format or minify buttons to adjust spacing or copy the sanitized JSON to clipboard.

Common JSON Syntax Errors and Fixes

| Error Type | Broken Example | Correct Valid JSON | | :--- | :--- | :--- | | **Single Quotes** | `{'id': 1}` | `{"id": 1}` | | **Trailing Comma** | `{"items": [1, 2,],}` | `{"items": [1, 2]}` | | **Unquoted Key** | `{name: "Alice"}` | `{"name": "Alice"}` | | **Unescaped Quotes** | `{"bio": "He said "Hi""}` | `{"bio": "He said \"Hi\""}` |

Frequently Asked Questions

How does this JSON validator locate syntax errors?
It runs a recursive token parser that catches syntax exceptions and pinpoints the precise character index, line number, and token where brackets, quotes, or commas mismatch.
Why does JSON require double quotes instead of single quotes?
The RFC 8259 and ECMA-404 standards strictly require double quotes for string values and object keys to maintain uniform compatibility across programming languages like C, Java, Python, and Go.