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Validate JSON syntax instantly and get precise error messages with line and column numbers, structural type, key count, and byte size.
Follow these simple steps to get instant, accurate results directly in your browser:
Enter or paste the JSON text you want to validate into the input editor.
Review the live status banner. If errors are present, inspect the exact line and column report.
Inspect payload metrics (structural type, key/item count, and byte size) and copy your validated JSON.
The JSON Validator is a developer utility that parses, lints, and checks JSON data against RFC 8259 and ECMA-404 specifications, identifying malformed structures and invalid data types instantly.
Unlike basic parsers that only throw generic 'Unexpected token' exceptions, our validator pinpoints the exact line and character column where errors happen. It explains common syntax mistakes such as single quotes instead of double quotes, trailing commas in objects or arrays, unquoted keys, NaN/Infinity literals, and improper escape characters.
All parsing executes inside your client-side JavaScript engine. Private payloads containing user credentials or customer data remain strictly on your device.
Identifies the exact location of syntax violations in payloads.
Provides actionable guidance on syntax errors without exposing internal stack traces.
Calculates structural type, object key or array item counts, and payload byte size.
Validates payloads locally in browser memory with zero server requests.
Verify mock server fixtures and seed datasets before running test suites.
Validate incoming webhook bodies from Stripe, GitHub, or Shopify.
Learn strict JSON syntax rules and discover why JavaScript object literals fail JSON validation.
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