DEVELOPER TOOL · PRIVATE
JavaScript Minifier Online
Conservatively reduce JavaScript whitespace and comments.
Create a smaller JavaScript snippet with conservative local minification. Paste the input, make the change, then read the result before you copy it elsewhere.
Keep source maps and original source for serious projects.
Ready — input is processed locally.
This utility runs on the current device for the supported workflow. Kaazo does not need the pasted input to calculate the result.
JavaScript Minifier is a narrow tool on purpose
Create a smaller JavaScript snippet with conservative local minification.
Minification should change size, not meaning
Removing whitespace and comments is useful only while the output still parses the same way. Strings, regular expressions and significant whitespace are exactly where simplistic minifiers can go wrong.
Run your own tests after minifying production code. JavaScript grammar has edge cases—especially around regular-expression literals and automatic semicolon insertion.
When JavaScript Minifier isn’t the right endpoint
Use a production build tool when you need advanced JavaScript/CSS optimisation, bundling, source maps or compatibility transforms.
Example and result checks
Use a simple, non-critical function as a first test, then run both versions with the same inputs. A shorter file must still produce the same values and browser behaviour. JavaScript syntax has special cases around strings, regular expressions, comments and automatic semicolon insertion that are easy to damage with simplistic replacements.
If the input uses modules, source maps, decorators or framework transforms, a dedicated compiler or bundler is usually the correct tool. Compare console output and test important interactions after changing scripts. Keep the readable source for debugging; a successful parse alone does not prove the code remains equivalent.
FAQ
What does JavaScript Minifier actually do?
Create a smaller JavaScript snippet with conservative local minification.
What limitation matters most?
Removing whitespace and comments is useful only while the output still parses the same way. Strings, regular expressions and significant whitespace are exactly where simplistic minifiers can go wrong. Run your own tests after minifying production code. JavaScript grammar has edge cases—especially around regular-expression literals and automatic semicolon insertion.
Does formatted or converted output prove the data is valid for my application?
No. JavaScript Minifier can perform the syntax or data operation described here, but your application can still impose its own schema, business rules, encoding or security requirements.
Related tools
After JavaScript Minifier, validate the output before feeding it into another transform. The data-format guide has broader context if you need it.