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Validate JSON syntax before it blows up in production

“Looks fine” is not a parser. Paste the string, get a clear valid/invalid result and an error message you can act on. This page is for **syntax** — not JSON Schema.

chars: 17
Input
Output

When to use

You inherited a webhook body, edited a config by hand, or suspect copy-paste truncated a brace — and you need a clear valid/invalid answer before shipping.

Examples

Input
{"ok":true,"n":1}
Output
Valid JSON
Input
{"ok":true,}
Output
Invalid — unexpected token near the trailing comma
Exact error text depends on the engine.

How it works

Attempts JSON.parse. On failure it surfaces the message (and position when available). On success you get a pass — not schema rules, not pretty-print.

Common pitfalls

  • Valid syntax ≠ correct shape — use JSON Schema Validator for required fields/types.
  • Never eval JSON; always parse.
  • NaN, Infinity, and undefined are not valid JSON values.

How this differs

Validator = syntax only. Formatter needs valid input then indents it. Schema Validator checks an instance against a draft schema.

FAQ

What’s the difference vs Schema validator?
Syntax = well-formed JSON. Schema = shape/types against a draft schema.
Does valid JSON mean safe to eval?
No. Never `eval` JSON; always parse.
Are comments allowed?
Not in standard JSON.
Is data uploaded?
No.

Related tools

Runs in your browser. Nothing is uploaded. Not a security product —hashes and JWT decode are for debugging, not password storage or auth advice.