Is my JSON data sent to a server?

No. All formatting and validation happens entirely in your browser. Your data never leaves your machine, making it safe for sensitive API keys and tokens.

What indentation styles are supported?

You can choose between 2-space, 4-space, or tab indentation. The default is 2 spaces, which is the most common convention in web development.

Can I format large JSON files?

Yes. The formatter handles files up to several megabytes efficiently since all processing is done locally using your browser's JavaScript engine.

Format JSON Online Free

Paste messy or minified JSON and get perfectly formatted output in one click. This free browser-based formatter validates your JSON syntax and applies consistent indentation so you can read and debug data structures faster.

Open JSON Formatter

How It Works

// Input (minified)
{"name":"Alice","roles":["admin","editor"],"active":true}

// Output (formatted)
{
  "name": "Alice",
  "roles": [
    "admin",
    "editor"
  ],
  "active": true
}

Common Use Cases

Prettifying API responses for debugging
Validating JSON config files before deployment
Formatting JSON logs from production systems
Preparing JSON payloads for documentation

Frequently Asked Questions

Is my JSON data sent to a server?: No. All formatting and validation happens entirely in your browser. Your data never leaves your machine, making it safe for sensitive API keys and tokens.
What indentation styles are supported?: You can choose between 2-space, 4-space, or tab indentation. The default is 2 spaces, which is the most common convention in web development.
Can I format large JSON files?: Yes. The formatter handles files up to several megabytes efficiently since all processing is done locally using your browser's JavaScript engine.