Vue 2 vs Vue 3: Key Differences and When to Use Each

Vue 3 introduces the Composition API for better code organization and improved performance over Vue 2's Options API. It also supports Fragments, Teleport, and better TypeScript integration, making Vue 3 more modern and flexible.

Quick Comparison

Here is a quick side-by-side look at the main differences between Vue 2 and Vue 3.

Feature	Vue 2	Vue 3
API Style	Options API only	Composition API + Options API
Performance	Good	Up to 50% faster rendering
TypeScript Support	Limited	Built-in and improved
Fragments Support	No (single root element required)	Yes (multiple root elements allowed)
New Features	No Teleport or Suspense	Teleport, Suspense, and better reactivity
Bundle Size	Larger	Smaller and more tree-shakable

Key Differences

Vue 3 introduces the Composition API, which lets developers organize code by logical concerns rather than component options. This makes complex components easier to manage and reuse. Vue 2 relies solely on the Options API, which groups code by options like data, methods, and computed.

Performance improvements in Vue 3 come from a rewritten virtual DOM and better optimizations, resulting in faster rendering and smaller bundle sizes. Vue 3 also supports Fragments, allowing components to return multiple root elements, unlike Vue 2 which requires a single root element.

TypeScript support is native in Vue 3, making it easier to build typed applications. Additionally, Vue 3 adds new features like Teleport for moving DOM elements outside the app root and Suspense for handling async components gracefully, which Vue 2 lacks.

Code Comparison

This example shows a simple counter component in Vue 2 using the Options API.

vue

export default {
  data() {
    return {
      count: 0
    };
  },
  methods: {
    increment() {
      this.count++;
    }
  },
  template: `<div>
    <p>Count: {{ count }}</p>
    <button @click="increment">Increment</button>
  </div>`
};

Output

A button labeled 'Increment' and a text showing 'Count: 0' that increases by 1 each click.

Vue 3 Equivalent

The same counter component in Vue 3 using the Composition API.

vue

<script setup>
import { ref } from 'vue';
const count = ref(0);
function increment() {
  count.value++;
}
</script>
<template>
  <div>
    <p>Count: {{ count }}</p>
    <button @click="increment">Increment</button>
  </div>
</template>

Output

A button labeled 'Increment' and a text showing 'Count: 0' that increases by 1 each click.

When to Use Which

Choose Vue 3 when starting new projects for better performance, modern features, and improved TypeScript support. It is ideal for complex apps needing flexible code organization with the Composition API.

Use Vue 2 if you maintain legacy projects or rely on libraries not yet compatible with Vue 3. Vue 2 remains stable and widely supported but lacks the latest improvements.

Key Takeaways

Vue 3 offers better performance and modern features like the Composition API and Fragments.

Vue 2 uses the Options API and requires a single root element per component.

Vue 3 has built-in TypeScript support and new features like Teleport and Suspense.

Choose Vue 3 for new projects and Vue 2 for legacy support or incompatible libraries.