Guides/camelCase vs PascalCase vs snake_case

camelCase vs PascalCase vs snake_case

These styles all join multi-word names without spaces. The difference is capitalization and whether underscores appear.

What they look like

• camelCase: helloWorldExample — first word lower, later words capitalized.
• PascalCase: HelloWorldExample — every word capitalized (also called UpperCamelCase).
• snake_case: hello_world_example — lowercase with underscores.

When to use which

• camelCase — JavaScript/TypeScript variables and functions; JSON fields in many APIs; Java methods.
• PascalCase — class names (Java, C#, TypeScript); React components; some public types.
• snake_case — Python names (PEP 8); many database columns; some Ruby and Rust conventions.

Worked examples

1. Phrase: user account id
   camelCase → userAccountId
   PascalCase → UserAccountId
   snake_case → user_account_id
2. React: component UserProfile (PascalCase); prop userName (camelCase).
3. Python: function get_user_name; class UserProfile still PascalCase by convention.
4. URLs still prefer kebab-case — see snake vs kebab.

Common mistakes

• Mixing camelCase JSON with snake_case DB columns without an explicit mapping layer.
• Using PascalCase for ordinary JavaScript variables (works, but fights community style).
• Putting hyphens in identifiers where the language treats - as minus.

Convert related styles

The freeCase Converterhandles UPPER, lower, Title, sentence, snake_case, and kebab-case — handy when preparing names before you apply camel/Pascal by hand. Also:title vs sentence case.