Code Formatter
Format, validate and minify JSON, CSS, HTML, SQL and JavaScript. Real-time output. Free, private, no upload.
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Output
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About Code Formatter
Poorly formatted code is harder to read, harder to debug, and harder to review. Whether you receive minified output from an API, auto-generated markup from a CMS, or disorganized SQL from a legacy system, reformatting it by hand wastes time. Our Code Formatter handles JSON, CSS, HTML, SQL, and JavaScript — beautifying with Prettier and sql-formatter, minifying in the same panel, and colour-highlighting the result so you can actually read it.
For JSON specifically, the formatter also validates the structure and reports the parser's error message along with the line where it failed — essential when debugging an API response or configuration file that is failing to parse. Minified JSON from production systems often contains subtle errors (trailing commas, unquoted keys) that only become visible when formatted with proper line breaks.
All formatting runs locally in your browser. No code, credentials, database queries, or proprietary business logic is ever transmitted to a server. This makes it safe to format sensitive configuration files, internal SQL queries, or company source code that should not leave your device.
How to Use Code Formatter
- 1Paste your code into the input field, or click "Upload File" to load a code file directly.
- 2Pick the language tab — JSON, CSS, HTML, SQL or JavaScript. Switching tabs clears both panels.
- 3Choose an action: Format, Minify or Validate. The available actions change per language — only JSON offers Validate, and SQL is format-only.
- 4The output refreshes on its own about half a second after you stop typing, so there is nothing to press.
- 5For JSON, validation runs on every pass — invalid input shows the parser message and the line where it broke, instead of the formatted output.
- 6Click "Copy" to copy the result, or the download button to save it with the right extension (.json, .css, .html, .sql or .js).
Use Cases
- →Beautify minified JSON from an API response for readable debugging
- →Format and validate JSON configuration files to catch syntax errors before deployment
- →Clean up auto-generated HTML or CSS before submitting code for review
- →Reformat SQL queries for readability before adding to documentation or a README
- →Quickly pretty-print JavaScript received from a third-party snippet or library
- →Validate JSON structure in configuration files, environment variable files, or API payloads
- →Shrink a JSON payload or CSS file with the built-in Minify action before pasting it into production
- →Open a .json, .css, .sql or .js file straight from disk with the Upload File button, without pasting
Tips
- ✓JSON validation runs automatically — invalid input shows the parser error message and the line number where it failed
- ✓Output is always indented with 2 spaces, the most common convention for JSON, CSS and JavaScript
- ✓JavaScript formatting follows Prettier defaults: single quotes, semicolons and ES5 trailing commas
- ✓SQL formatting uppercases every keyword (SELECT, FROM, WHERE, JOIN) and puts a blank line between separate queries
- ✓For very large files (multi-MB JSON exports), processing takes a few seconds — all in your browser
- ✓Upload File reads the file with the browser File API — like everything else here, nothing is sent anywhere
- ✓The status bar under the panels reports the output line count and byte size, handy for checking what Minify actually saved
Frequently Asked Questions
The formatter supports JSON, CSS, HTML, SQL and JavaScript. Each language has its own tab with specific actions — JSON includes validation with error line detection, SQL formats keywords in uppercase.
As you type, the formatter processes your code automatically after a 500ms pause. You can also switch between Format, Minify, and Validate modes at any time — the output updates instantly.
If your JSON has a syntax error, the output panel shows the exact error message and the line number where the error was found.
Yes. Click "Upload File" above the input panel and pick a file — its contents are read straight into the editor with the browser's File API, so nothing is uploaded anywhere. Editing the text afterwards is fine; the formatter re-runs as you type.
Not yet — output is always indented with 2 spaces, the most common convention for JSON, CSS and JavaScript. SQL keywords are additionally uppercased, and JavaScript follows Prettier's defaults: single quotes, semicolons and ES5 trailing commas.
Format adds indentation and line breaks to make code readable. Minify removes all unnecessary whitespace and comments to reduce file size. Both preserve the code's behavior.
The SQL formatter automatically indents your queries, converts all SQL keywords (SELECT, FROM, WHERE, JOIN, etc.) to uppercase, and adds line breaks between clauses.
No. All formatting, validation and minification happens entirely in your browser using JavaScript. Your code never leaves your device.