JSON Validator
JSON Validator
Validate JSON or NDJSON syntax with strict or lenient parsing, then inspect structure metrics and output formatting.
Result
Valid JSON
object root • 4 keys • depth 3 • 78 bytes. No duplicate keys detected.
Validation setup
Quick actions
Strict mode validates raw JSON syntax only. Standard mode runs full duplicate-key detection and full schema issue cap.
Privacy
Flow
- Parse input in JSON or NDJSON mode using strict or lenient normalization.
- If parsing fails, report error location with line and column context.
- Optionally validate parsed payload against the in-browser JSON Schema subset.
- Return normalized output in formatted or minified mode with optional key sorting.
Example
Worked example: valid object payload
- 1 Input: {"id":42,"name":"Ada"}
- 2 Parser succeeds with object root
- 3 Output is formatted with indentation
The payload is valid JSON and ready for use.
How
- Paste JSON or NDJSON text into the input editor.
- Choose strict/lenient validation and optional schema mode.
- Switch to large payload mode for faster validation on bigger inputs.
- Copy formatted/minified output and report details when checks pass.
Avoid
- Leaving trailing commas after the last key or array item.
- Using single quotes instead of double quotes.
- Forgetting to quote object keys.
FAQ
Does this validator run locally?
Yes. Validation happens in your browser and data is not uploaded.
Can it show line and column hints?
Yes, parser error context includes line and column whenever available.
Does it support schema validation?
Yes, schema mode validates against an in-browser JSON Schema subset and reports path-level issues.
Does it warn about duplicate object keys?
Yes, duplicate keys are flagged because standard JSON parsers keep only the last value.
Can it handle large JSON payloads?
Yes, large payload mode keeps validation responsive by reducing expensive scans while preserving core parse checks.
Can I validate arrays and primitives?
Yes, any valid JSON root type is supported.
Switch
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