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JSON Formatter

Format, validate and pretty-print JSON. Catches syntax errors with line and column numbers.

Updated

What is the JSON Formatter?

The JSON Formatter cleans up messy or minified JSON into a neatly indented, readable format, while also validating whether the JSON structure is correct.

Features

  • Paste JSON data directly into the input box
  • Automatically formats and validates JSON in real time
  • Choose formatting options:
  • Indent with 2 spaces
  • Indent with 4 spaces
  • Minify JSON into a compact single-line format
  • Instantly highlights invalid JSON for quick debugging

How to Use

  1. Paste your JSON into the input area
  2. Select your preferred formatting style (indent or minify)
  3. Copy the formatted output instantly

Common Use Cases

  • Debugging API responses
  • Reading configuration files
  • Inspecting log payloads
  • Cleaning up minified production JSON

Privacy

All processing happens entirely in your browser. No data is uploaded, stored, or transmitted anywhere.

How it works

The formatter uses the browser’s native JSON engine to process your input efficiently and reliably.

Processing Flow

  • The input is first parsed using JSON.parse()
  • If parsing succeeds, the data is re-serialized using JSON.stringify() with your selected formatting option:
  • 2-space indentation
  • 4-space indentation
  • Minified (single-line) output
  • If parsing fails, the tool captures the exact error position from the JSON engine
  • The error is then converted into a readable message, including:
  • Line number
  • Column position
  • Clear explanation of the issue

Common Errors It Helps You Detect

The formatter makes it easier to spot and fix typical JSON problems, such as:

  • Trailing commas
  • Missing or mismatched quotes
  • Extra or misplaced brackets
  • Structural syntax errors

Privacy & Performance

All processing happens locally in your browser using native JavaScript APIs. No data is sent to any server, ensuring fast performance and complete privacy.

Examples

Pretty-print a one-liner

A compact object expanded to 2-space indentation.

{"id":1,"ok":true}
{
  "id": 1,
  "ok": true
}

Catch a syntax error

A trailing comma is reported with its location.

{ "a": 1, }
Invalid JSON: Unexpected token } (line 1, column 11)

Frequently asked questions

What does the JSON Formatter do?

It validates JSON input and formats it into a clean, readable structure using consistent indentation. Key capabilities include:

  • Converts minified JSON into a structured, readable format.
  • Supports adjustable indentation levels for customized readability.
  • Can also minify JSON into a compact single-line format when needed.

How does it report errors?

When invalid JSON is detected, the tool provides detailed and precise error feedback. It includes:

  • Clear parsing error messages.
  • Exact line and column numbers where the error occurs.
  • Guidance for common issues such as:
  • Missing or mismatched quotes
  • Trailing commas
  • Incorrect or unbalanced brackets

Is my data sent to a server?

No. All processing happens locally in your browser using the built-in JSON.parse() engine. Your data:

  • Never leaves your device.
  • Is not uploaded or transmitted anywhere.
  • Is processed entirely in a secure local environment.

Can it minify JSON as well as format it?

Yes. The tool supports both formatting and minification modes.

  • The Minify option removes all unnecessary whitespace.
  • Outputs the smallest valid JSON representation.
  • Useful for reducing payload size in APIs and storage.

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