Skip to main content
{ }JSON Formatter·Free online tool

JSON Formatter & Beautifier

Paste any JSON and instantly beautify it with customizable indentation, optional key sorting, and minification. Validates structure in real time with clear, plain-English error messages — everything runs entirely in your browser, nothing is sent to a server.

Formatting Options

Indent
Formatted JSON will appear here…

How to Use This Tool

  1. 1

    Paste your JSON into the editor, or click 'Load sample' to try an example. Tab key inserts spaces like a real code editor.

  2. 2

    If your JSON has fixable issues (missing brackets, trailing commas), a yellow banner appears — click 'Apply to Input' to fix it automatically.

  3. 3

    Click ✨ Prettier to reformat your JSON in-place with clean 2-space indentation (Prettier's default style).

  4. 4

    Choose your preferred indentation: 2 spaces, 4 spaces, or tabs. Toggle 'Sort keys A–Z' or 'Minify' as needed.

  5. 5

    The formatted output appears instantly with syntax highlighting and line numbers. Click 'Copy' to copy it to your clipboard.

See It in Action

Common formatting operations and their output:

Beautify compact JSON
Input
{"name":"Jane","age":25,"active":true}
Output
{ "name": "Jane", "age": 25, "active": true }
Auto-fix trailing comma
Input
{"name":"Jane","age":25,}
Output
{ "name": "Jane", "age": 25 }
Sort keys
Input
{"zebra": 1, "apple": 2, "mango": 3}
Output
{ "apple": 2, "mango": 3, "zebra": 1 }
Minify formatted JSON
Input
{ "x": 10, "y": 20 }
Output
{"x":10,"y":20}

About the JSON Formatter Tool

The JSON Formatter & Beautifier is a free online JSON editor that makes working with JSON fast, forgiving, and painless. Whether you received a compact API response, need to clean up a broken config file, or want to commit well-formatted JSON to version control, this tool handles it in under a second — with zero configuration and no data ever leaving your browser.

Features

  • ·Smart auto-fix: detects and repairs missing brackets, trailing commas, and incomplete structures
  • ·✨ Prettier button: reformat input in-place with Prettier's default 2-space style
  • ·Code editor UI: line numbers, Tab key support, and monospace font on both input and output
  • ·Syntax highlighting: keys, strings, numbers, booleans, and null each get a distinct colour
  • ·Three indent options: 2 spaces, 4 spaces, or tabs
  • ·Deep key sorting for consistent, diff-friendly output
  • ·Minification for compact, production-ready JSON
  • ·Real-time validation with descriptive, plain-English error messages
  • ·No size limits — handles large payloads entirely in your browser
Free foreverNo sign-upWorks offlinePrivacy-firstAuto-fixPrettier support

Frequently Asked Questions

A JSON formatter (also called a JSON beautifier or pretty printer) takes compact or minified JSON and adds indentation and line breaks to make it human-readable. It also validates that the JSON structure is syntactically correct.

Yes — the formatter includes smart auto-fix logic. If your JSON has common issues like missing closing brackets or braces, trailing commas, or incomplete structure, it will detect and fix them automatically, showing you exactly what was corrected. You can apply the fix to the input with one click.

Clicking ✨ Prettier formats your JSON in-place using Prettier's default style: 2-space indentation and clean, consistent structure. It also applies any available auto-fixes before formatting. This is ideal when you want to commit clean JSON to version control.

Minifying JSON removes all whitespace, newlines, and indentation to produce the most compact representation possible. This reduces file size, which is useful for network transmission or storage.

Sorting keys alphabetically orders all object keys A–Z at every nesting level. This is useful for comparing two JSON objects, normalizing API responses, or producing deterministic output for version control.

2 spaces is the most common convention (used by Prettier, JavaScript, Node.js, npm). 4 spaces matches Python and many style guides. Tabs are preferred in some codebases for accessibility and configurable visual width.

Yes — all processing happens entirely in your browser using JavaScript. Your JSON is never sent to any server or stored anywhere.

JSON has strict syntax rules: keys must be double-quoted strings, trailing commas are not allowed, and values must be strings, numbers, booleans, null, arrays, or objects. The error message pinpoints exactly where the syntax breaks. Use the auto-fix feature to resolve common issues automatically.

All processing runs in your browser — your JSON never leaves your device.

Related Text Tools