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Browser-based tool

JSON Validator

Validate JSON syntax instantly and get a parser result you can act on before sending data further downstream.

Input JSON Waiting

Validation result Parser output

Validation is immediate and stays local to the browser, which keeps the workflow fast and private.

Is this JSON tool free?

Yes. It is free to use, and it runs right in the browser.

Is my JSON uploaded anywhere?

No. Your JSON stays in the page. Formatting, validation, comparison, and conversion all happen locally.

What makes JSON invalid?

Most failures come from missing quotes, comments, trailing commas, or broken nesting.

Does this validator change my data?

No. It just checks whether the parser can read it.

A lot of broken requests come down to one comma, quote, or bracket in the wrong place.

Catching that early is easier than discovering it later through a failed deploy or a vague API error.

Single quotes, comments, trailing commas, and `undefined` are fine in some JavaScript contexts but not in JSON.

If the data came from code, serialize the object properly instead of pasting a JavaScript literal into a JSON file.

Format JSON with clean indentation so logs, payloads, and fixtures are easier to read.

Strip whitespace from JSON when you need a compact payload.

Convert JSON to YAML for config files, manifests, and CI jobs.

Paste your input at the top and the result shows up right below. The FAQ and related tutorials are there if you want more.

Most tools run entirely in your browser.
Your input isn't sent to a server unless a tool says it makes a network request.
Related tools and tutorials sit below when a task usually needs a follow-up.