Code Formatter
Beautify or minify JSON, HTML, JavaScript, CSS, SQL, XML, and PHP in your browser. See byte-size differences and detect syntax errors — nothing is sent.
Disclaimer: Free tool provided “as is” by MonitorGiant. No warranty or liability for any data loss, security issues, or infrastructure problems arising from use of this tool. Results are for informational purposes only. · A Free Tool by MonitorGiant
What is Code Formatter?
The Code Formatter beautifies or minifies source code in seven languages: JSON, HTML, JavaScript, CSS, SQL, XML, and PHP. Beautifying adds consistent indentation and line breaks to make code human-readable; minifying strips all whitespace to reduce file size for production. The tool also detects syntax errors in JSON, reports them with line and column numbers, and shows the before/after byte difference so you can see exactly how much space minification saves.
How to use this tool
- 1 Select your language from the tab bar at the top (JSON, HTML, JS, CSS, SQL, XML, or PHP).
- 2 Paste your code into the left editor pane.
- 3 Click 'Beautify' to format with indentation, or 'Minify' to strip whitespace for production.
- 4 The formatted output appears in the right pane — click 'Copy' to copy it to your clipboard.
- 5 For JSON, any syntax errors are highlighted with a red banner showing the line and column number.
When would you use this?
- Receiving a minified API response (e.g. a JSON payload or HTML fragment) and needing to read or debug it quickly.
- Preparing CSS or JavaScript for a production deployment where every byte counts and you want to minimise file size.
- Reformatting SQL queries from a query builder that outputs everything on one line, making them readable for a code review.
How Code Formatter works
The Code Formatter processes your code entirely inside the browser — no upload, no server, no waiting. It supports seven languages and works offline once the page has loaded.
- 1
Select the language and action
Choose from JSON, HTML, JavaScript, CSS, SQL, XML, or PHP. Then pick Beautify (add indentation and whitespace) or Minify (strip whitespace to reduce file size).
- 2
Paste your code
Drop your raw, minified, or unformatted code into the input panel. The tool auto-detects JSON and HTML from the first character when you paste.
- 3
Validation and parsing
JSON uses JSON.parse() for strict validation. HTML and XML use the browser's DOMParser. JavaScript and CSS are processed by the bundled js-beautify library. SQL and PHP use custom formatters.
- 4
Beautified or minified output
Beautify adds consistent 2-space indentation and line breaks. Minify strips comments and collapses whitespace. Not all languages support minify — SQL and PHP are beautify-only.
- 5
Size comparison
The tool shows the byte size of both input and output and the percentage change — useful for understanding how much bandwidth minification saves.
Your code never leaves the browser. JSON uses JSON.parse()/JSON.stringify(). HTML/XML use the browser's native DOMParser. JavaScript and CSS use js-beautify (bundled, no CDN). SQL and PHP use inline formatters. Nothing is sent to MonitorGiant or any third party.
Looking for a free online JSON formatter or JSON beautifier? JSON must be syntactically valid before it can be pretty-printed — this tool parses your input and pinpoints the exact line where an error occurs, so you can fix malformed JSON fast. For HTML, it uses the browser's native parser to reformat nested markup with proper indentation. Also supports JavaScript, CSS, SQL, XML, and PHP — covering every file type you'd paste during a code review, debugging session, or API integration.
Frequently asked questions — Code Formatter
How do I format and validate JSON online?
Paste your JSON into the input box, make sure the JSON language tab is selected, and click Beautify (or press Ctrl+Enter). The tool uses the browser's native JSON.parse() for strict validation — if your JSON has a syntax error, you'll see the exact position where parsing failed along with a hint about the most common causes, such as unquoted property names, single quotes instead of double quotes, or trailing commas.
What is the difference between beautify (format) and minify?
Beautify adds consistent indentation, line breaks, and spacing to make code easy to read and debug. Minify does the opposite — it removes all unnecessary whitespace, comments, and formatting to produce the smallest possible file size. Minified code is ideal for production (faster page loads), while beautified code is easier to work with during development. The size comparison bar shows exactly how many bytes each operation saves or adds.
Can I format JavaScript, CSS, SQL, XML, and PHP too?
Yes — this tool supports seven languages: JSON, HTML, JavaScript, CSS, SQL, XML, and PHP. JavaScript and CSS are formatted using the bundled js-beautify library. SQL is formatted with a custom keyword-uppercasing and clause-separation formatter. XML uses the browser's DOMParser and a custom serialiser. PHP uses js-beautify's JavaScript mode, which handles PHP syntax reasonably well for formatting purposes.
Why does JSON.parse throw an error when my input looks correct?
The most common JSON mistakes are: (1) using single quotes instead of double quotes around strings or property names — JSON requires double quotes; (2) not quoting property names at all, e.g. {key: "value"} instead of {"key": "value"}; (3) leaving a trailing comma after the last item in an array or object; (4) using undefined, NaN, or Infinity as values — these are JavaScript-specific and not valid JSON. The tool provides specific hints for each of these cases.
Is my code sent to any server when I format it?
No. All formatting happens entirely in your browser. The JSON, HTML, and XML formatters use browser-native APIs (JSON.parse, DOMParser). The JavaScript and CSS formatters use the js-beautify library, which is bundled into the page and runs locally. No code is transmitted to MonitorGiant or any other server. The tool works completely offline once the page has loaded.
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