camelCase vs snake_case vs kebab-case: When to Use Each

Every naming convention looks arbitrary until you notice that each one actually maps to a specific technical context — and mixing them up is one of the fastest ways to make code (or a URL) look inconsistent.

camelCase

firstName, getUserData — the first word lowercase, each subsequent word capitalized, no separators. This is the standard convention for variables and function names in JavaScript, Java, and several other languages.

snake_case

first_name, get_user_data — all lowercase, words separated by underscores. This is the conventional style for Python variables and functions, and it's also extremely common for database column names across nearly every language.

kebab-case

first-name, user-profile-page — all lowercase, words separated by hyphens. This is the standard for URLs (search engines and readability both favor hyphens over underscores in slugs) and is common in CSS class names and HTML attributes.

PascalCase

UserProfile, GetUserData — like camelCase but with the first letter capitalized too. This is the standard for class and component names across most object-oriented and component-based languages.

Why consistency matters more than which one you pick

Most of these conventions aren't objectively "better" than the others — they're just what a given language's ecosystem has standardized on. A JavaScript codebase mixing camelCase and snake_case variable names isn't broken, but it reads as inconsistent and makes the code slightly harder to scan.

Quick reference

• JavaScript variables/functions: camelCase
• Python variables/functions: snake_case
• Database columns: snake_case
• URLs and CSS classes: kebab-case
• Class/component names: PascalCase

The bottom line

Match the convention to the context — the language or platform you're working in almost always already has a standard, and following it makes code easier for anyone else (including future you) to read.