What Is camelCase? A Developer's Guide

camelCase is a naming convention for compound identifiers: the first word is lowercase, each following word starts with an uppercase letter, and there are no spaces, hyphens, or underscores between words. Examples: userProfile, totalAmount, isActive.

Where you will see camelCase

• JavaScript and TypeScript variables and functions
• JSON property names in many web APIs
• Java bean properties and Kotlin identifiers (with conventions similar to JS)
• Configuration keys in some libraries and frameworks

JavaScript examples

const userProfile = getUserProfile();
function calculateTotalAmount(items) {
  return items.reduce((sum, item) => sum + item.unitPrice, 0);
}

The variable and function names use camelCase. Class names in JavaScript typically use PascalCase instead (see below).

JSON and API fields

{
  "firstName": "Ada",
  "lastName": "Lovelace",
  "isActive": true
}

Many REST APIs return camelCase keys. If you are mapping database columns in snake_case to a JSON response, a converter can save manual renaming during prototyping.

camelCase vs other naming styles

• camelCase — userProfile: variables and JSON keys in JS ecosystems.
• PascalCase — UserProfile: classes, React components, and some type names.
• snake_case — user_profile: Python, Ruby, SQL columns, and many config files.
• kebab-case — user-profile: URLs, CSS classes, and HTML attributes.

Tricky inputs

Multiple input formats

Good converters accept plain phrases (user profile), snake_case (user_profile), kebab-case (user-profile), and spaced Title Case (User Profile). They split on spaces, underscores, hyphens, and case boundaries, then join in the target style.

Acronyms and numbers

The phrase HTML parser typically becomes htmlParser: each word is lowercased, then word boundaries are capitalized. That may not match your team's style guide if you prefer HTMLParser. Numbers are usually kept as-is (user2fa, v2Api). When in doubt, fix acronyms manually after converting.

Convert a phrase to camelCase

Paste any phrase into the camelCase Converter. Processing stays in your browser.

Related naming tools: PascalCase, snake_case, and kebab-case converters are on the same site if you need a different output style.