String Case Converter

Different languages, file systems, and config formats each favor a particular naming convention, and converting between them by hand is tedious and error-prone. This tool takes any phrase and renders it in every common case at once: camelCase, PascalCase, snake_case, CONSTANT_CASE, kebab-case, Title Case, and Sentence case.

How it works. The converter first splits your input into words — recognizing spaces, underscores, hyphens, dots, and the case boundaries inside camelCase and PascalCase — then re-joins those words in the target style. That means it can convert from any convention to any other: paste user_access_token, UserAccessToken, or user access token and get all forms.

Where each convention lives. camelCase is typical for JavaScript/Java variables; PascalCase for class and type names; snake_case for Python, Ruby, and SQL columns; CONSTANT_CASE for environment variables and constants; kebab-case for URLs, CSS classes, and CLI flags. Title Case and Sentence case are for prose — headings and UI labels — not identifiers. Picking the right one keeps code idiomatic and avoids the subtle bugs that come from inconsistent naming, and it matters beyond code: a URL slug is conventionally kebab-case because search engines treat hyphens as word separators but not underscores, so user-access-token reads as three words where user_access_token reads as one.

Worked example. Feed the tool user access token, user_access_token, or UserAccessToken and it returns every other form — userAccessToken, USER_ACCESS_TOKEN, user-access-token, and so on. Because it splits on case boundaries as well as separators, it round-trips from any convention, which is what makes it useful for porting a field name between a database column, a JSON API, and a UI label.

Common mistakes. Names that mix acronyms (parseJSONURL) split unpredictably in naive converters; this tool treats runs of capitals reasonably, but review acronym-heavy identifiers. Also remember that case conventions carry semantic weight in some contexts — environment variable names are conventionally upper-case, and on case-sensitive file systems Config.json and config.json are different files. Renaming a file only by case on a case-insensitive system (Windows, default macOS) can silently fail or confuse version control.

A security aside. Case handling is occasionally security-relevant. Case-insensitive comparisons of usernames or emails can let Admin and admin collide or bypass a blocklist; conversely, assuming case-insensitivity where the system is case-sensitive (Linux paths, S3 keys, some databases) creates gaps. When normalizing identifiers for a security decision, define the canonical form explicitly and apply it consistently on both the storing and checking side, using Unicode-aware casing to avoid homoglyph and Turkish-I style pitfalls.