Which case goes where
Every ecosystem settled on different conventions, and moving data between them means converting constantly. JavaScript and Java use camelCase for variables and PascalCase for classes and components. Python and Ruby use snake_case for variables and functions. Database columns are usually snake_case. URLs, CSS classes and file names use kebab-case. Environment variables and constants use CONSTANT_CASE.
The friction shows up at every boundary: an API returning snake_case JSON consumed by a camelCase frontend, a database column mapped to a class property, a design token becoming a CSS variable. Converting a whole list at once is considerably faster than retyping each name and introducing a typo in one of them.
The conversions that are harder than they look
Acronyms are where naive converters fall apart. Converting HTTPResponse to snake_case should give http_response, not h_t_t_p_response. Going the other way, parse_url_string should become parseUrlString or parseURLString depending on your house style - and both are defensible, which is why teams argue about it.
Numbers and separators cause the other half of the trouble. Should user2Name split before the digit? Does an existing hyphen count as a word boundary? Consistent handling matters most when you are converting a batch, because one inconsistent result in a list of eighty is the one that breaks a build.
Frequently asked questions
- What is the difference between camelCase and PascalCase?
- Both join words without separators. camelCase starts with a lowercase letter and is used for variables; PascalCase capitalises the first letter too and is used for classes and components.
- What is kebab-case used for?
- Lowercase words joined by hyphens. It is the convention for URLs, CSS class names, and file names, largely because hyphens are safe and readable in all three.
- How are acronyms handled?
- Acronyms are treated as single words, so HTTPResponse converts to http_response rather than splitting into individual letters.
- Can I convert a whole list at once?
- Yes. Paste multiple lines and each is converted independently, which is the fast way to rename a set of database columns or API fields.