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JSON Validator & Schema Checker
JSON Input
Validation Result
Paste JSON to validate

Free Online JSON Validator — Validate JSON Syntax Instantly

Paste any JSON and get instant validation with exact line and column error positions. Check the JSON specification rules and get fix suggestions.

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RFC 8259 Compliant

Validates against the official JSON specification (RFC 8259). Catches all syntax errors including trailing commas, unquoted keys and incorrect escape sequences.

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Exact Error Position

Shows the precise line and column number where the error occurred. The error context panel highlights the problematic character directly.

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Fix Suggestions

Common errors come with actionable fix suggestions. Trailing comma? We tell you where. Missing closing bracket? We say which line it should be on.

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File Upload

Upload .json files directly — useful for validating configuration files, API response exports or data files without copy-pasting large amounts of text.

Frequently Asked Questions

What is JSON validation?
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JSON validation checks that your JSON follows the official syntax rules (RFC 8259). A validator confirms: all keys are quoted strings, all strings use double quotes, there are no trailing commas, and all brackets and braces are correctly matched.
What is the difference between JSON validation and JSON formatting?
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Validation checks whether your JSON is syntactically correct — it either passes or fails. Formatting (beautification) makes valid JSON more readable by adding indentation. You need valid JSON before you can format it.
What causes a JSON validation error?
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The most common causes are: trailing comma after the last item in an object or array, single quotes instead of double quotes, an unquoted key, undefined or NaN values (not valid in JSON), and mismatched or missing brackets.
Can I validate a JSON file?
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Yes — click Upload and select a .json file. The file is read locally and validated without uploading to any server.
What does the line and column number mean?
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The error position shows exactly where in your JSON the parser failed. Line 3, Column 12 means the error was found on the third line, at the 12th character. Use this to jump directly to the problem.
Is JSON validation the same as JSON schema validation?
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No — syntax validation checks the JSON format. Schema validation checks that the data matches a defined structure (required fields, data types, allowed values). This tool performs syntax validation. For schema validation, use a dedicated JSON Schema library in your application code.