JSON Formatter
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Output
Formatted JSON will appear here

What is this JSON Formatter?

This is a free, real-time JSON formatter and validator that runs 100% in your browser. No data is sent to any server. It supports formatting (beautifying), minifying, sorting keys alphabetically, and real-time validation with line-accurate error messages.

How does JSON formatting work?

JSON.parse() converts your text into an in-memory JavaScript object, then JSON.stringify() renders it back with proper indentation. This also validates the JSON as a side effect " any syntax errors are caught and displayed with the exact character position.

Is my data safe?

All processing is done entirely in your browser's memory using JavaScript. No data is sent to any server. When you close this tab, the data is gone. This makes it safe to use with API keys, tokens, or private configuration files.

What does "Sort Keys" do?

It recursively sorts all object keys alphabetically throughout the entire JSON structure. Useful for comparing two JSON objects for differences or enforcing consistent key ordering in config files.

What is JSON minifying?

Minifying removes all whitespace, newlines, and indentation from valid JSON. The result is functionally identical but smaller " useful for reducing payload size in HTTP API responses or configuration files.

Copied! "

How to Use This Tool

Transform compact or messy JSON into beautifully indented, human-readable output with syntax highlighting.

  1. Paste your compact JSON into the input pane.
  2. Select your preferred indentation level — 2 spaces, 4 spaces, or Tab.
  3. Click "Format" to prettify. The output appears instantly with color-coded syntax highlighting for strings, numbers, booleans, and null values.
  4. Click "Copy" to grab the prettified JSON, or "Download" to save it as a clean .json file.
  5. Use "Sort Keys" if you want alphabetically ordered keys for consistency.

What Is JSON Prettifier Online?

A JSON prettifier takes valid but hard-to-read JSON — typically minified API responses or machine-generated output — and adds consistent indentation, line breaks, and formatting to make the data structure visually clear.

This tool uses JSON.stringify(data, null, indent) to insert your chosen indentation at each nesting level. The output pane renders the result with syntax highlighting, making strings (green), numbers (orange), booleans (purple), and null values visually distinct.

All processing runs in your browser. No data is uploaded to any server. This makes it safe to prettify JSON containing sensitive data like API tokens, user records, or internal configuration.

Why You Need This

Why prettifying JSON matters for your workflow:

Pro Tips for Best Results

Frequently Asked Questions

What is the difference between prettifying and formatting JSON?

They are the same operation. Both add consistent indentation and line breaks to make JSON human-readable. "Prettifying," "beautifying," and "formatting" are interchangeable terms in the JSON context.

Does prettifying change the data in my JSON?

No. Prettifying only adds whitespace (spaces, tabs, newlines). The actual data — keys, values, arrays, objects — remains identical. JSON.parse() will produce the exact same JavaScript object from both the minified and prettified versions.

Why does my prettified JSON look different from the original?

The original may have used inconsistent indentation (mixing tabs and spaces) or different indent sizes. This tool standardizes all indentation to your chosen format, producing clean, consistent output.

Can I prettify JSON that contains Unicode characters?

Yes. JSON fully supports Unicode. Characters like emojis, Chinese characters, or special symbols will be preserved exactly as they are in the prettified output.

What indent size should I use for my project?

2 spaces is the most common convention in JavaScript/TypeScript projects and is the default in tools like Prettier. 4 spaces is common in Python and Java ecosystems. Tabs are preferred by developers who want each team member to control their own visual width.

How large of a JSON file can I prettify?

Files up to 10-20 MB prettify instantly on modern browsers. The limit depends on your device's available RAM since all processing happens client-side in JavaScript.