Developer
JSON Syntax Checker
- Browser-based
- No signup
This JSON syntax checker parses your document and reports the first blocking error—missing brackets, bad escapes, or wrong types. Use it when linters are unavailable or you need a quick browser check.
Errors report the first failure; fix iteratively until the document parses cleanly.
100% Client-Side
Your data never leaves your computer.
How to use this tool
Paste invalid JSON, read the error message, jump to the line indicated, and revalidate.
Worked example
Example: `{name: "test"}` fails—keys must be quoted as `"name"` in valid JSON.
When to use this
- Quick checks on copied API responses.
- Validating LLM-generated JSON.
- Teaching students common JSON mistakes.
Common mistakes
- Smart quotes from Word docs.
- BOM characters at file start.
- Mixing JSON with JavaScript object syntax.
Related long-tail tasks
- json unexpected token
- escape quotes in json
- validate json schema
How it works
Paste JSON to validate syntax instantly. Invalid JSON shows parse errors with line and column when available. Validation runs entirely in your browser.
Limitations
Validates JSON syntax only. Schema, business rules, and duplicate keys are not checked unless noted.
Privacy and file handling
Your data is processed in your browser and is not uploaded to our server.
Related JSON Validator guides
These pages use the same json validator with guides tailored to specific search intents.
- JSON Validator — general payment estimate
- Validate JSON Online
- Validate JSON Syntax
- JSON Lint Checker
- Check JSON Online
Frequently asked questions
Schema validation?
This checks syntax only—not JSON Schema or required fields.
Is data sent to a server?
Validation runs locally in your browser on Utilnivo.
Array vs object root?
Both are valid if syntax is correct; root must be one JSON value.
Related tools
Related pages
- Browse all free online tools on Utilnivo
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