JSON Validator
Check JSON syntax, structure, and locate the exact error positions instantly.
Valid JSON
Your JSON structure is perfectly formed.
JSON Input
JSON Validator & Syntax Checker Online
Finding a missing comma or an unescaped quote in a massive JSON payload can be incredibly frustrating. Our free online JSON Validator instantly checks your JSON code for syntax errors, structural issues, and validation rule violations.
100% Local Validation: To protect your data, our JSON syntax checker runs entirely within your browser. Your API payloads and configurations are never uploaded to any server.
Core Features
- Instant Error HighlightingOur JSON Linter instantly pinpoints the exact line and character where your JSON breaks, saving you hours of manual debugging.
- Auto-FormattingOnce your JSON is valid, use the integrated formatter to pretty-print your data and make it instantly readable.
- Strict Standard ComplianceOur engine ensures your payload adheres strictly to the RFC 8259 JSON specification—no trailing commas, unescaped quotes, or single quotes allowed.
Example: Catching Errors
Invalid JSON Input
{
"user": "Alice",
"age": 28, <-- Trailing comma!
}Fixed & Valid JSON
{
"user": "Alice",
"age": 28
}Related Tools
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Categories
Frequently Asked Questions
What are the most common JSON errors?
The most frequent issues that break JSON syntax include: trailing commas at the end of objects or arrays, using single quotes instead of double quotes for strings, missing quotes around keys, and unescaped characters within strings.
Can I validate large JSON files?
Yes! Because our validator runs entirely within your browser using highly optimized client-side processing, you can validate multi-megabyte JSON files instantly without waiting for network requests.