Case converter

A case converter turns text between naming styles: camelCase, PascalCase, snake_case, SCREAMING_SNAKE_CASE, kebab-case, Train-Case, dot.case, flatcase, UPPERCASE, lowercase, Title Case, and Sentence case. Paste in a phrase or a list of identifiers and this tool shows every style at once.

Is my data uploaded anywhere?

No. Everything runs in your browser with plain string operations, no external library or server call involved. Nothing you type is sent anywhere, which matters if the text comes from a private codebase, a client’s config file, or anything else you’d rather not paste into a random website.

How does it know where one word ends and the next begins?

The converter splits on spaces, hyphens, underscores, and dots first, then looks inside each remaining chunk for case and digit boundaries. A lowercase letter followed by an uppercase one starts a new word, which is how fooBar becomes “foo” and “Bar.” A run of capital letters gets split before its last letter when a lowercase letter follows, so an acronym like HTTPServer splits into “HTTP” and “Server” instead of treating the whole thing as one capitalized block. Digits get their own rule: a run of digits always ends the word before it, but a digit right after a letter stays glued to it, so parseJSON2CSV splits into “parse,” “JSON2,” and “CSV,” keeping the “2” attached to the acronym it follows.

UPPERCASE and lowercase are the two exceptions to all of this: they just change the case of every letter directly and leave your original spacing, hyphens, and underscores untouched, since flattening everything to one case doesn’t need word boundaries in the first place. Every other style rebuilds the text from the detected words using its own separator and capitalization rules. Multi-line input is converted line by line, so line breaks in a pasted list stay in place.

Where does this come up?

This comes up whenever you’re moving a name across contexts with different conventions: turning a JSON field into a database column, renaming a JavaScript variable to match a CSS class, or converting a spreadsheet header into an environment variable. See MDN’s guide to JavaScript variable naming and the Wikipedia article on naming convention (programming) for background on why these styles exist.