ToolBirch

JSON Validator

Validate JSON syntax with the exact line and column of any error.Developer Tools

JSON Validator

Validate JSON syntax with the browser's own parser. Errors are reported with the line and column where parsing stopped.

Paste JSON above to validate it.

About this tool

A trailing comma, a smart quote, an unescaped newline — JSON fails on small details. This validator parses your document with the browser's own engine and, when it fails, translates the parser's error position into a line and column you can jump to.

How to use the JSON Validator tool

  1. Paste your JSON. Any single JSON document, however large your browser's memory allows.
  2. Read the verdict. Valid documents are confirmed at once; invalid ones show the parser error with a line and column.
  3. Fix and re-check. Edit the input and the validation is recomputed as you type.

Supported formats

Input

  • JSON text

Output

  • Valid/invalid verdict
  • Error message with line and column

Inputs are validated before anything is processed. Invalid values and unsupported files are rejected with a clear error instead of failing silently.

Frequently asked questions

Which grammar is enforced?

Strict RFC 8259 JSON through the browser's JSON.parse — comments and trailing commas are rejected.

How accurate is the position?

It points at the exact character where the parser stopped, which is usually at or just after the mistake.

Does it check schema or types?

No. This is syntax validation; structure rules belong to a JSON Schema validator.

Is my data sent anywhere?

No. Parsing runs locally and the page works offline once loaded.

Privacy

Everything you enter stays in this browser tab. There is no upload endpoint for tool inputs, no account, and no server-side copy of your text or files. Results are produced locally and disappear when you close the page.

No account is required and no file is ever uploaded. See the privacy policy for details about analytics and the limited data this site stores.

Known limitations

  • Syntax only — no JSON Schema or type checking.
  • Comments and trailing commas are invalid and reported as errors.
  • Very large documents are limited by tab memory.

Related tools

Other free tools from the same collection.

JSON FormatterFormat, validate and minify JSON with clear error positions.JSON MinifierStrip whitespace from JSON without touching string contents.JSON to YAMLConvert a JSON document into clean, correctly indented YAML.YAML to JSONParse YAML with js-yaml and emit clean, formatted JSON.