How to use it
- Paste code, drop a file or load the sample; the language is preset for this page and can be changed.
- Choose format or minify and adjust indent, width and other options; the result appears on the right as you type.
- Copy or download the result; on an error, use "Go to error", fix it and run again.
What minification does
Minifying changes how code is written, not what it does. It typically cuts 30–70% of the size and speeds up pages; keep your source, because minified code is hard to read.
| Operation | JavaScript（Terser） | CSS（CSSO） | HTML / XML / JSON |
|---|---|---|---|
| Remove comments | ✓ | ✓ | ✓ |
| Remove whitespace and line breaks | ✓ | ✓ | ✓ |
| Shorten variable names | ✓ | — | — |
| Merge rules, shorten colours | — | ✓ | — |
| Drop dead code, fold constants | ✓ | — | — |
| Keep /*! licence comments | Optional | Optional | Optional |
Languages and engines
Formatting uses the same open-source engines as popular editors, so results match Prettier in VS Code and your team can keep one style. Every engine loads from this site and runs in your browser.
| Language | Format | Compress |
|---|---|---|
| HTML | Prettier 3 | ✓ comments and whitespace |
| XML | XunL XML engine | ✓ |
| CSS / SCSS / Less | Prettier 3 | ✓ CSSO restructuring |
| JavaScript / TypeScript | Prettier 3（Babel） | ✓ Terser (JavaScript only) |
| JSON | Prettier 3 | ✓ big numbers keep precision |
| YAML | Prettier 3 | — (comments kept) |
| SQL | sql-formatter (14 dialects) | — |
Frequently asked questions
Is "merge duplicate rules" safe?
CSSO merges rules only when the cascade result stays the same. If a page relies on rule order and looks wrong, turn it off for basic minification only.
Is my code uploaded?
No. The engines download from this site and run in your browser; your code never passes through our servers or any third party, so it is safe for internal code and configuration.
How large can files be?
Up to 5 MB per file; above 300 KB the page waits for the button instead of formatting as you type, to keep the browser responsive.