JSON Formatter & Validator

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Data / Local tool

JSON Formatter & Validator

Format, minify, and check JSON in one editable workspace with precise line and column errors.

Your JSON stays in your browser

01 / JSON input

Edit and check JSON

88 characters / 5 lines

Valid JSON. No syntax errors found.

Standard JSON only. Comments and trailing commas are invalid.

How it works

Format and validate JSON in three steps

Work directly in the editor, choose the output you need, then copy or save the finished JSON without uploading it.

  1. 01
    Paste or type JSON.

    Replace the sample with an object, array, string, number, boolean, or null value.

  2. 02
    Format, minify, or validate.

    Use readable two-space indentation, remove whitespace outside strings, or check the syntax as written.

  3. 03
    Copy or download the result.

    Copy the current text or download valid JSON as a local .json file.

01 / Errors

Find invalid JSON by line and column

Syntax errors identify the exact line and column to check. Choosing Format, Minify, or Validate also moves the editor cursor to that position.

02 / Fidelity

Pretty-print JSON without changing values

Formatting changes whitespace only. Number text, escaped characters, property order, and duplicate property names remain exactly as entered.

03 / Privacy

Keep JSON data on your device

Validation, formatting, copying, and file creation happen in your browser. JSON content is not sent to Nanomite or placed in the page URL.

Standard JSON

What the validator accepts

The validator follows standard JSON syntax, so property names need double quotes and comments, trailing commas, NaN, and Infinity are rejected. It checks syntax only; it does not repair data or validate a JSON Schema.