Code Formatters — unminify JavaScript, CSS and HTML

How to use Code

Drop your source into the left pane, pick an indent style — two spaces, four, or tabs — and press format. The right pane shows the result, ready to copy. Formatting runs locally in the browser, so proprietary code stays on your machine, which matters more with code than with most text.

What a JavaScript beautifier actually fixes

Beautifying is purely cosmetic surgery: the program's behavior does not change, only its layout. Typical transformations: splitting a single enormous line of minified output into readable statements; normalizing indentation so nesting depth is visible at a glance;

spacing out operators and commas that a minifier squeezed together; putting each chained method call where a human can follow the chain. What it cannot do is bring back what minification destroyed: original variable names, comments, and file structure are gone for good. For that you'd need source maps, not formatting. Beautified code still has the same bugs — you can just finally see them.

When to beautify, and when to leave it alone

Reading a third-party script, debugging a production bundle, reviewing what a build tool actually emitted — all fair reasons to run an online javascript beautifier. The one place formatted output does not belong is back in production: shipped JavaScript should stay minified, because every space you add is a byte every visitor downloads. Beautify to read; minify to ship; never confuse the directions.

Debugging as a procedure

Debugging goes badly when it becomes guessing. It goes well when it becomes a procedure that narrows down the possible causes. Reproduce the problem reliably — an intermittent bug you cannot trigger cannot be fixed with confidence.

Reduce it to the smallest case that still fails. State what you believe is happening, then find the observation that would prove you wrong. Check the assumption you are most sure about, because that is where the bug hides.

Fix it, then confirm the original reproduction now passes. The third step is the one people skip. A hypothesis you only try to confirm will feel supported by almost anything. A hypothesis you try to break either survives or dies quickly, and both outcomes are progress.

Deleting more than you add

Codebases grow by default. Things get added and rarely removed, because adding is visibly useful and removing feels like it risks something. Over time this produces systems where a large fraction of the code is not reached, not needed, or duplicated somewhere else with small differences nobody remembers the reason for.

Removing that code is not cleanup for its own sake. Every unused path is something a reader has to understand before deciding it is irrelevant, and something a change has to be checked against. Deleting it makes the remaining code cheaper to work with. The best-reviewed changes are frequently the ones where the total line count goes down.