Web ToolBox

JSON Formatter

Syntax check and beautify JSON formatting

Indentation
Indent Spaces
Input
Result
Read-only

What is JSON Formatter?

A quick, reliable tool to make JSON easy to read and to help you spot syntax mistakes fast. It focuses on clear, consistent formatting and actionable error messages so you can debug or inspect data more efficiently.

  • ✅ Real-time syntax checking with highlighted errors
  • ✅ Clean, configurable indentation and line breaks for better readability
  • ✅ Output modes: spaces, tabs, or compact (minified) depending on your needs

Common use cases: inspecting API responses, editing config files, debugging JSON outputs, and teaching/learning JSON structure.

How to Use

  1. Paste or type a JSON string into the input (left) area.
  2. The tool parses the input and checks for syntax errors automatically. If there are errors, the offending line is highlighted with a concise message.
  3. View the formatted JSON in the output (right) area. Changing settings updates the output immediately.

If an error appears, fix the highlighted issue (for example, a missing comma or a misplaced quote) and re-check until the JSON is valid.

Format Settings

Adjust the output formatting to match your workflow. These settings are available in the tool UI and take effect immediately.

Indent

Choose the indentation style that suits your project or personal preference.

  • Spaces (default) — readable and widely used
  • Tabs — lets your editor control visual width
  • Compact (minified) — removes line breaks and extra spacing for smaller output

Indent width (when using spaces)

Recommended values when using spaces:

  • 2 spaces — lightweight and common in many frontend projects (default)
  • 4 spaces — often used in larger projects or server-side code

6–8 spaces are rarely needed, choose them only if required by a specific style guide.

JSON Basics

Quick rules to check when you get a syntax error:

  • Strings must use double quotes (")
  • Objects use { } and arrays use
  • Key/value pairs use a colon (:)
  • Items are separated by commas (,) — trailing commas are not allowed

Example:

{
  "name": "John Doe",
  "age": 30,
  "hobbies": ["reading", "traveling"]
}

See the MDN guides for a deeper reference: