String Case Formats — When to Use What
Every programming language and environment has conventions. Using the wrong case in the wrong place causes linting errors, merge conflicts, and "why does this look wrong" code reviews.
camelCase
Default for variables and functions in JavaScript, Java, TypeScript, Swift, Dart. First word lowercase, each subsequent word capitalized. getUserById, fetchAllRecords.
PascalCase
Used for class names, React components, TypeScript interfaces, C# types. Every word capitalized. UserProfile, HttpRequestHandler, ProductCard.
snake_case
Standard in Python, Rust, Ruby, SQL column names. All lowercase, words joined by underscores. user_profile_data, fetch_all_records.
SCREAMING_SNAKE_CASE
Global constants, environment variables, macros. API_BASE_URL, MAX_RETRY_COUNT, DATABASE_HOST. Instantly signals "do not change this value."
kebab-case
CSS class names, HTML attributes, URL slugs, CLI flags, npm package names. background-color, user-profile, --output-file.
dot.notation
Config file keys (NGINX, .properties files), i18n translation keys, some logging systems. server.host, app.database.port, errors.auth.invalid.