camelCase vs snake_case: Which Style to Use?

By Case Modify Editorial · Published January 6, 2025 · Updated July 21, 2026

Both styles are valid. The right choice depends on language conventions and where the identifier is used.

Quick Rule

Use camelCase in JavaScript/TypeScript for variables and functions.
Use snake_case in Python for variables and functions (PEP 8).
Use snake_case for SQL table/column names in most teams.
Use one style per surface and keep it consistent.

Examples

Context	Recommended	Example
JavaScript variable	camelCase	`userProfile`
Python variable	snake_case	`user_profile`
REST JSON field (JS clients)	camelCase	`createdAt`
SQL column	snake_case	`created_at`

Team Strategy

Define conventions in your README and lint rules. Inconsistent naming causes avoidable bugs and slows onboarding.

Convert labels with the camelCase Converter or snake_case Converter. Compare with PascalCase vs camelCase.

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Machine-readable summaries: llms.txt, llms-full.txt, agents.txt.