JavaScript Beautifier

A JavaScript beautifier takes compressed or poorly formatted JavaScript and rewrites it with proper indentation, spacing, and line breaks so it becomes readable again. Minified scripts collapse an entire file onto one line, strip every optional space, and sometimes mangle variable names down to single letters. That is ideal for shipping but hopeless when you need to understand what a bundle is doing in production. This tool restores structure by indenting each block, putting statements on their own lines, adding spaces around operators, and breaking up chained expressions so the control flow is visible. It understands modern syntax, including arrow functions, template literals, destructuring, spread and rest, async and await, optional chaining, nullish coalescing, and ES module import and export statements. It is important to be clear about what beautifying does and does not do. It changes whitespace and line breaks only, it does not run, validate, or fix your code. If the input has a syntax error, the formatted output still has that error, although broken structure is usually far easier to spot once the code is indented. Beautifying also cannot recover original variable names that a minifier already mangled to single characters, since that information is permanently lost during minification. The result is readable code, not the original authored source. TypeScript and JSX are not fully supported because they introduce syntax that is not plain JavaScript, so type annotations and JSX tags may not indent perfectly. Everything runs locally in your browser, so proprietary or unreleased source code is never transmitted. For the opposite direction, the companion JavaScript Minifier compresses code for production.