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Validate, format, and beautify your JSON data with detailed error reporting and syntax highlighting.
Paste your JSON data or upload a .json file for validation.
The validator checks syntax, structure, and formatting in real-time.
See detailed error messages with line numbers and suggestions for fixes.
Beautify your JSON with custom indentation and copy the formatted result.
Instant syntax checking as you type with live error highlighting.
Precise error messages with line numbers and column positions.
Beautify JSON with customizable indentation (2, 4, or 8 spaces).
Upload .json files for validation and formatting.
All validation happens in your browser — no data sent to servers.
The validator detects missing brackets, trailing commas, unquoted keys, invalid escape sequences, duplicate keys, and all syntax errors defined by the JSON specification (RFC 8259). It pinpoints the exact line and column of each error.
Yes, the validator handles large JSON files efficiently. Processing happens in your browser, so performance depends on your device.
Yes, paste minified JSON and the formatter will beautify it with proper indentation and line breaks. You can choose 2-space, 4-space, or tab indentation.
JSON (JavaScript Object Notation) is defined by RFC 8259 and ECMA-404. Valid JSON must use double-quoted strings, cannot have trailing commas, does not support comments, and requires specific escape sequences for special characters. Our validator checks against these exact rules.
Absolutely. Paste any API response to validate its structure, format it for readability, and identify issues like malformed arrays or objects.
JSON (JavaScript Object Notation) is governed by two standards: RFC 8259 (IETF) and ECMA-404 (Ecma International). Valid JSON must follow strict rules — all strings must be double-quoted, no trailing commas are allowed, no comments are permitted, and specific escape sequences must be used. Common validation errors include trailing commas after the last array element (legal in JavaScript but not in JSON), single-quoted strings, and unescaped control characters. Our validator checks your JSON against the full specification and provides actionable error messages.
This tool is particularly useful when: