React vs Vue vs Svelte vs Solid in 2024: Performance, Bundle Size, and When to Choose Each

React, Vue, Svelte, and Solid are all choices for building reactive web UIs in 2024. They share concepts — reactivity, components, props — but differ significantly in architecture and approach. This guide compares them with Firefox DevTools integration in mind.

The Problem They Solve

Without a framework, updating the DOM in response to state changes requires manual work:

let count = 0;

document.getElementById('btn').addEventListener('click', () => {
  count++;
  document.getElementById('counter').textContent = count; // Manual sync
});

Frameworks automate the "update the DOM when state changes" part.

React: The Incumbent

React uses a virtual DOM — changes are diffed against a virtual tree and only necessary DOM updates happen.

import { useState } from 'react';

function Counter() {
  const [count, setCount] = useState(0);

  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={() => setCount(count + 1)}>Increment</button>
    </div>
  );
}

Key concepts:

• useState, useEffect, useMemo, useCallback hooks
• Virtual DOM diffing
• One-way data flow (props down, events up)
• Server components (React 19+)

Performance in Firefox:
React renders can be profiled in the Firefox Performance tab. Long tasks (>50ms) show in the flame graph. React DevTools extension provides component-level timing.

Vue: The Progressive Framework

Vue is more prescriptive with a clear structure. Its Composition API (Vue 3) is similar to React hooks:

<template>
  <div>
    <p>Count: {{ count }}</p>
    <button @click="count++">Increment</button>
  </div>
</template>

<script setup>
import { ref } from 'vue';
const count = ref(0);
</script>

<style scoped>
button { padding: 8px 16px; }
</style>

Key concepts:

• Single-file components (template + script + style)
• Reactivity via ref() and reactive()
• Directives: v-if, v-for, v-bind, v-model
• Built-in transition system

Performance: Vue uses a compiler to optimize templates at build time — fewer runtime comparisons than React.

Svelte: Compile-Time Reactivity

Svelte has no virtual DOM. It compiles components to vanilla JavaScript that directly manipulates the DOM:

<script>
  let count = 0;
</script>

<p>Count: {count}</p>
<button on:click={() => count++}>Increment</button>

That's it — no imports needed. Svelte compiles this to DOM manipulation code.

Key concepts:

• Reactive assignments: count++ automatically updates the DOM
• $: reactive statements (runs when dependencies change)
• Stores for shared state
• Zero runtime in the browser (no framework to download)

Bundle size: A Svelte app ships ~2KB of runtime vs React's ~45KB. For performance-critical apps, this matters.

Solid: React-like but Faster

Solid looks like React but compiles to direct DOM updates (like Svelte):

import { createSignal } from 'solid-js';

function Counter() {
  const [count, setCount] = createSignal(0);

  return (
    <div>
      <p>Count: {count()}</p>
      <button onClick={() => setCount(count() + 1)}>Increment</button>
    </div>
  );
}

Key concepts:

• Signals: fine-grained reactivity (only updates what changed)
• No virtual DOM — direct DOM updates
• JSX compiled to DOM operations
• createSignal, createEffect, createMemo (similar to React's hooks)

Performance Comparison

In Firefox DevTools:

• Open Performance tab → Record
• Click through your app
• Stop recording
• Analyze the flame graph

What to look for:

• React: "React" frames in the flame graph, batch updates
• Vue: compiled getter/setter calls, virtual DOM patches
• Svelte: direct DOM updates with no framework overhead visible
• Solid: signal subscriptions and fine-grained updates

Measured render performance (rough order, fastest first):

1. Solid (fine-grained reactivity, no VDOM)
2. Svelte (compiled to direct DOM ops)
3. Vue (optimized compilation)
4. React (VDOM diffing, though React 19 improves this)

For most apps, these differences don't matter. They matter for: many DOM nodes updating simultaneously, 60fps animations driven by state changes, large data tables.

Choosing in 2024

Choose React if:

• Largest ecosystem and job market
• Need React Native for mobile
• Your team already knows it

Choose Vue if:

• Want an opinionated structure
• Building moderately complex apps
• Like single-file components

Choose Svelte if:

• Bundle size matters (content sites, embedded widgets)
• Want the simplest syntax
• SvelteKit is your preferred meta-framework

Choose Solid if:

• Maximum performance is critical
• React API familiar but need faster rendering
• Building very reactive, data-heavy UIs

Firefox Extensions and Framework Choice

Firefox WebExtensions can use any framework for popup/options UIs. Svelte is popular for extensions because of its minimal bundle size — popup UIs that ship 45KB of React feels heavyweight.

A Svelte popup UI might ship as 3-5KB of JavaScript. A React equivalent might be 50-60KB (though still fast — just larger download).

For Tab Manager & Session Saver, the session management UI benefits from reactive frameworks — displaying dozens of tabs, updating state as tabs open/close.