NextTool

JSON Formatter

How to use

Makes messy JSON easy to read by adding proper spacing and indentation. You can also shrink it to save space, check if it is valid, and explore it as a tree. Paste your JSON in the box and the formatted version appears. Use the buttons to copy, download, or switch between tree and code view.

Developer PopularLocal only
runs live, on-device
Valid · 244 chars
Input244 chars · 16 lines
Output
{
  "appName": "NextTool",
  "version": "1.0.0",
  "isPrivate": true,
  "theme": "Dark & Light",
  "features": [
    "Formatters",
    "Encoders",
    "Generators",
    "Regex"
  ],
  "config": {
    "localStorage": true,
    "workers": 2
  }
}
When to use this
  • Catching a malformed JSON payload before it hits production, using the validation and repair features
  • Beautifying a minified API response to inspect its structure during debugging
  • Minifying a config file before deploying it to reduce payload size
  • Exploring a deeply nested API response using the tree view instead of scrolling raw text

Free and private. Everything runs on your own device, with no account and no uploads.

API developers debugging a malformed response payload, and backend engineers reviewing a config file, both need to quickly turn a wall of unformatted JSON into something readable. This formatter beautifies JSON with proper indentation, minifies it to save space, validates syntax and attempts basic repair of common mistakes, and offers a tree view so you can explore nested objects and arrays visually instead of scrolling through raw text.

It includes a basic repair feature that can fix common issues like trailing commas or missing quotes, but severely malformed JSON may still need manual correction.

Yes, the tree inspector lets you expand and collapse objects and arrays so you can navigate deeply nested structures without scrolling through raw text.

Since formatting happens in your browser, very large JSON files are limited by your device memory rather than a fixed server-side limit.

Standard JSON does not support comments, so if your input contains comment-like text it may cause a validation error rather than being stripped automatically.

How it works
  1. 1

    Paste your JSON

    Add raw or minified JSON into the input panel.

  2. 2

    Choose an action

    Select Format to beautify, Minify to compact, or Validate to check syntax.

  3. 3

    Switch to tree view

    Explore nested objects and arrays interactively in the tree inspector.

  4. 4

    Fix errors if flagged

    Use the repair option or the reported error location to correct invalid JSON.

  5. 5

    Copy the formatted result

    Copy the cleaned-up JSON for use in your code or API tool.

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Pro tips
  • ·Use the tree view for deeply nested structures, collapsing branches is far faster than scanning indentation by eye.
  • ·The repair feature handles common issues like trailing commas, but treat it as a starting point, not a guarantee, for badly malformed input.
  • ·Remember standard JSON does not support comments, comment-like text will trigger a validation error rather than being stripped.