Consistent naming is one of the quiet hallmarks of clean code. Most languages and teams settle on a convention for variables, functions, files and constants — and knowing the differences helps you read and write code that fits in anywhere.
The four conventions
camelCase joins words with no spaces and capitalises every word except the first (userName). PascalCase capitalises every word including the first (UserName) and is common for classes and types. snake_case joins lowercase words with underscores (user_name). kebab-case uses hyphens (user-name) and is popular for URLs and CSS classes.
Which convention where?
JavaScript and Java favour camelCase for variables and PascalCase for classes. Python and Ruby prefer snake_case. CSS and URLs use kebab-case. SCREAMING_SNAKE_CASE is reserved for constants. The golden rule is to follow the dominant style of the language or codebase you are working in.
Convert names instantly
Refactoring identifiers by hand invites typos. A case converter tokenises your text — handling spaces, camel humps and acronym runs — and rewrites it in any convention, so you can move a name between languages or styles in one click.