camelCase

/ˈkæm.əl.keɪs/

noun — “the naming style where words huddle together and capital letters pop up like camel humps.”

camelCase is a naming convention in programming where multiple words are joined together without spaces, the first word starts with a lowercase letter, and each subsequent word begins with an uppercase letter. This style is widely used for variables, function names, and method identifiers, especially in languages and ecosystems that emphasize readability and concision. The visual rhythm of capital letters helps humans parse word boundaries quickly, even when identifiers grow long.

In everyday development, camelCase is most commonly associated with languages such as JavaScript, Java, and many modern scripting environments. It works closely with Variable Naming and Naming Convention practices to keep identifiers descriptive without becoming unwieldy. Compared to snake_case or kebab-case, camelCase avoids underscores or hyphens, which can be visually noisy in dense code or chained method calls.

camelCase also interacts with concepts like Code Quality and Best Practice. Consistent use of camelCase makes codebases easier to scan, reduces cognitive load during Code Review, and helps teams share a common visual language. In many projects, camelCase is reserved for variables and functions, while PascalCase is used for classes, creating a clear visual distinction between different kinds of identifiers.

In practice, camelCase shines when identifiers describe behavior or intent. Seeing a name like calculateTotalPrice immediately communicates action and meaning without punctuation or spacing. This readability advantage becomes more important as projects scale and more developers touch the same codebase.

A few practical examples show how camelCase is typically used in real code:

// JavaScript variables
let userName = "alex";
let totalItemCount = 42;
let isLoggedIn = true;

// Functions using camelCase
function calculateTotalPrice(items) {
    return items.reduce((sum, item) => sum + item.price, 0);
}

function fetchUserProfile(userId) {
    return api.getUser(userId);
}

// Mixing conventions for clarity
class UserProfile {          // PascalCase for classes
    constructor(userName) {
        this.userName = userName; // camelCase for properties
    }
}

Key considerations when using camelCase include consistency and audience expectations. Mixing camelCase with other conventions arbitrarily can harm readability and create confusion. Most teams document when camelCase should be used and enforce it with linters or formatting tools to maintain uniformity across the codebase.

camelCase is like reading a sentence with invisible spaces: your eyes know exactly where one word ends and the next one begins.

See Naming Convention, Variable Naming, PascalCase, snake_case, kebab-case.