beautifier

A beautifier, in computing, is a software tool that reformats text or source code to improve readability. It applies consistent indentation, spacing, line breaks, and, where appropriate, comment placement, without changing the program's semantics. In addition to code, beautifiers can format data formats such as JSON, XML, or HTML to produce a neatly nested, human-friendly representation.

Code beautifiers are often language-aware; they parse the source to preserve syntax and strings while adjusting layout. They offer options for style guides (for example, indentation size and maximum line length) and can be integrated into editors, IDEs, version control workflows, or automated build pipelines.

Common examples include Prettier and js-beautify for JavaScript, HTML, and CSS; Black and autopep8 for Python; and clang-format for C and C++. These tools help maintain a consistent style, reduce cognitive load during code reviews, and improve readability across teams.

Limitations include disagreements over preferred styles, the potential for formatting changes to obscure real issues in diffs, and the need to keep configurations up to date with evolving guidelines. Projects typically publish a single standard and enforce it with CI or pre-commit hooks.

See also: pretty printer, code formatter.