How to Format and Validate JSON Online
Turn messy JSON into clean, readable code — instantly in your browser.
What Is JSON?
JSON (JavaScript Object Notation) is the most widely used data format on the web. APIs, configuration files, databases, and web applications all use JSON to store and transmit structured data.
A simple JSON example:
{
"name": "John Doe",
"age": 30,
"email": "[email protected]",
"skills": ["JavaScript", "Python", "SQL"]
}Though JSON is human-readable, real-world JSON from APIs is often minified (compressed into a single line), making it nearly impossible to read without formatting.
Step-by-Step: Format JSON Online
Step 1: Open the JSON Formatter
Go to our free JSON formatter. It processes everything in your browser — your data stays private.
Step 2: Paste Your JSON
Paste your raw or minified JSON into the input area. The tool accepts any valid JSON structure — objects, arrays, nested data, etc.
Step 3: Format or Minify
Click "Format" to pretty-print your JSON with proper indentation, or "Minify" to compress it into a single line. If your JSON has syntax errors, the tool will highlight them.
Step 4: Copy the Result
Click "Copy Result" to copy the formatted JSON to your clipboard, ready to use in your code.
Common JSON Errors and How to Fix Them
| Error | Example | Fix |
|---|---|---|
| Trailing comma | {"a": 1,} | Remove the last comma |
| Single quotes | {'name': 'John'} | Use double quotes |
| Unquoted keys | {name: "John"} | Quote all keys |
| Missing comma | {"a": 1 "b": 2} | Add comma between values |
| Comments | // comment | Remove — JSON doesn't support comments |
Pretty-Print vs Minified JSON
Pretty-printed JSON uses indentation and line breaks for readability. It's ideal for development, debugging, and documentation.
Minified JSON removes all whitespace. It's ideal for production, API responses, and reducing bandwidth. A minified JSON response can be 30-60% smaller than its pretty-printed version.
Our tool lets you switch between both formats with a single click.
Why Format JSON in Your Browser?
Developers often paste sensitive data into JSON formatters — API keys, user records, configuration secrets. With cloud-based formatters, this data is sent to a server.
Our JSON formatter is 100% client-side. Your JSON is parsed using the browser's native JSON.parse() and JSON.stringify() — the data never leaves your device. Read more about why this matters.
Frequently asked questions
Does it support comments in JSON?
Native JSON does not support comments. Our tool follows the standard specification, but it can help you strip comments if you're cleaning up 'pseudo-JSON' for production use.
Can I format nested arrays and objects?
Yes. The formatter handles infinitely nested structures and large datasets effortlessly, providing consistent 2-space or 4-space indentation.
Does it work on mobile devices?
Absolutely. The interface is fully responsive. You can paste and format JSON directly from your phone's clipboard safely.
Format Your JSON Now
Paste, format, copy. 100% browser-based, 100% private.
{ } Format JSON