Text Case Conventions: When to Use Each

Text case conventions are tribal. Mixing them in one codebase causes friction; following the local convention is what matters.

The Major Cases

StyleExampleCommon Use

|-------|---------|------------|

camelCasegetUserByIdJavaScript, Java variables/functions PascalCaseUserAccountClass names, React components snake_caseget_user_by_idPython, Ruby, SQL SCREAMING_SNAKEMAX_RETRY_COUNTConstants in most languages kebab-caseuser-profileURLs, CSS classes, file names Train-CaseUser-ProfileHTTP headers (Content-Type) flatcasegetuserbyidrare; Go package names

Per-Language Defaults

• JavaScript/TypeScript: camelCase for variables, PascalCase for classes/components, SCREAMING_SNAKE for constants, kebab-case for filenames.
• Python: snake_case everywhere, PascalCase for classes, SCREAMING_SNAKE for constants.
• Rust: snake_case for everything except types and traits (PascalCase) and constants.
• Go: PascalCase exports, camelCase locals, no underscores or dashes.
• CSS: kebab-case classes, kebab-case custom properties (--brand-color).
• HTML attributes: kebab-case (data-user-id).
• JSON keys: usually camelCase, but snake_case when serving Python/Ruby backends.

Special Cases

• URLs: kebab-case is SEO-preferred (/blog/text-case-conventions over /blog/textCaseConventions).
• Filenames: kebab-case for assets and components; snake_case for Python modules; PascalCase for React component files in some teams.
• Database: snake_case columns by SQL convention; some teams force lowercase to avoid quoting.
• Environment variables: SCREAMING_SNAKE always (DATABASE_URL).

Acronyms

The fight no one wins:

• getUrl vs getURL vs getUrlAddress
• parseHTML vs parseHtml

Pick one. Modern style guides lean toward treating acronyms as words: getUrl, parseHtml. Easier to convert between cases mechanically.

Auto-conversion

function camelToKebab(s) { return s.replace(/[A-Z]/g, c => '-' + c.toLowerCase()); }

function kebabToCamel(s) { return s.replace(/-([a-z])/g, (_, c) => c.toUpperCase()); }

Most codebases have these utilities. Use them in serialization layers, not scattered through business logic.

Convert between cases instantly with the [Text Case Converter](https://sdk.is/text-case-converter).