JSON Validator
Validate JSON syntax instantly. Get precise error messages with line numbers. Checks structure, detects trailing commas, missing quotes, and more.
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Frequently asked questions
What is a JSON validator?
A JSON validator checks whether a string conforms to the JSON specification (RFC 8259). It parses the input and reports any syntax errors — including the exact line and column where the problem occurs — so you can fix them quickly.
What are the most common JSON syntax errors?
The four most frequent mistakes are: trailing commas after the last item in an object or array, single-quoted strings (JSON requires double quotes), unquoted property keys, and missing closing braces or brackets. This validator detects all of these and provides plain-language hints.
What's the difference between JSON validation and JSON Schema validation?
JSON validation checks syntax — whether the string is parseable JSON. JSON Schema validation checks semantics — whether the data matches a defined structure (required fields, value types, formats). This tool does syntax validation. For schema validation, use our JSON Schema Generator tool.
How do I validate JSON in JavaScript?
Wrap JSON.parse() in a try/catch. If it throws, the JSON is invalid and the error message contains the
position. This is exactly what this tool does internally — all in your browser, instantly.
Is this JSON validator safe to use with sensitive data?
Yes. Validation runs entirely in your browser. No data is sent to any server. You can safely paste API keys, tokens, and private records — nothing leaves your machine.