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Developer Tools · Free · No sign-up

JSON Validator

Validate JSON and see the exact line and column of any error. Free, private, no sign-up — runs in your browser.

Runs in your browser Nothing uploaded Instant, unlimited No sign-up

JSON Validator

Check whether a JSON document is syntactically valid. Errors are reported with line and column numbers plus a snippet of the offending region, and valid documents get a structure summary.

Validation result appears here…

About this JSON Validator

A strict syntax check against the JSON specification (RFC 8259) using the browser's native parser. When validation fails you get the line, column and a caret-marked snippet — far faster than hunting through a large payload by eye.

Frequently asked questions

What JSON standard is used?
The browser’s built-in parser, which implements RFC 8259 — the same strict grammar used by APIs everywhere.
Does it validate against a schema?
This tool checks syntax only. Schema validation (JSON Schema) checks structure and types and is a separate concern.
Why does it accept bare numbers like 42?
RFC 8259 allows any JSON value at the top level, including numbers, strings and booleans.
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