How to Use Composition API in Vue

The Vue.js framework has evolved significantly since its initial release, introducing powerful patterns that improve code organization, reusability, and scalability. One of the most transformative additions in Vue 3 is the Composition API. Unlike the Options API, which organizes logic by options (data, methods, computed, etc.), the Composition API lets developers group related logic by feature or concern — making complex components easier to read, maintain, and test.

As applications grow in size and complexity, managing state, side effects, and logic across multiple components becomes increasingly challenging. The Composition API directly addresses these challenges by enabling developers to write more modular, reusable, and predictable code. Whether you're building a small dashboard or a large enterprise application, understanding how to use the Composition API effectively is no longer optional — it's essential for modern Vue development.

In this comprehensive guide, you’ll learn how to use the Composition API in Vue from the ground up. We’ll walk through practical implementation steps, explore industry best practices, highlight essential tools, showcase real-world examples, and answer common questions. By the end of this tutorial, you’ll be equipped to refactor existing components, write new ones with confidence, and leverage the full power of Vue 3’s most innovative feature.

Step-by-Step Guide

Setting Up a Vue 3 Project with Composition API

Before diving into the Composition API, ensure your project is running Vue 3. The Composition API is not available in Vue 2 unless you install the @vue/composition-api plugin, which is now deprecated. For new projects, use the official Vue CLI or Vite to scaffold a Vue 3 application.

To create a new project using Vite — the recommended build tool for Vue 3 — run the following command in your terminal:

npm create vue@latest

Follow the prompts to select options like TypeScript, ESLint, and testing tools. Once the project is created, navigate into the directory and install dependencies:

cd my-vue-app
npm install

Start the development server:

npm run dev

By default, Vue 3 projects created with Vite use the Composition API in all new components. You’ll notice that the default App.vue file uses the