Solid.js vs Qwik

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Introduction

Solid.js and Qwik represent the cutting edge of web framework design. Both challenge the virtual DOM paradigm that has dominated frontend development for a decade, but they take radically different approaches. Solid.js offers fine-grained reactivity without a virtual DOM — updates are precise and surgical. Qwik introduces resumability, where applications can start on the server and resume on the client with almost no JavaScript. This comparison explores how these frameworks work and when to use each.

Solid.js

Solid.js was created by Ryan Carniato and pioneered the concept of fine-grained reactivity inspired by Knockout.js and MobX.

How it works:
Solid compiles your JSX into real DOM nodes wrapped in reactive computations. When state changes, only the specific DOM nodes depending on that state are updated — no virtual DOM diffing needed.

import { createSignal } from "solid-js";

function Counter() {
  const [count, setCount] = createSignal(0);
  const doubleCount = () => count() * 2;

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

Core concepts:

• Signals: Reactive primitives (createSignal) that track state
• Effects: Automatically re-run when dependent signals change (createEffect)
• Memos: Cached derived values that only recompute when dependencies change (createMemo)
• No virtual DOM: Direct DOM manipulation via compilation

// Solid.js: automatic dependency tracking
import { createSignal, createEffect, createMemo } from "solid-js";

const [todos, setTodos] = createSignal([]);
const [filter, setFilter] = createSignal("all");

const filteredTodos = createMemo(() => {
  switch (filter()) {
    case "active": return todos().filter(t => !t.done);
    case "completed": return todos().filter(t => t.done);
    default: return todos();
  }
});

// Automatically re-runs when filteredTodos changes
createEffect(() => {
  console.log(`Showing ${filteredTodos().length} todos`);
});

Strengths:

• Best-in-class runtime performance (no virtual DOM overhead)
• Predictable rendering — components render once, then reactively update
• Small bundle size (~7KB gzipped)
• Excellent TypeScript support
• React-compatible JSX (similar mental model to React)
• SolidStart meta-framework for full-stack applications

Weaknesses:

• Smaller ecosystem than React
• Fewer job opportunities
• JSX without re-rendering requires mental model shift from React
• Less community content and learning resources

Qwik

Qwik was created by Misko Hevery (creator of Angular) and introduces the concept of resumability.

How it works:
Qwik serializes application state on the server and sends minimal JavaScript to the client. Instead of downloading and executing the application to "rehydrate" it, Qwik "resumes" execution on the client — picking up exactly where the server left off.

import { component$, useSignal, $ } from "@builder.io/qwik";

export const Counter = component$(() => {
  const count = useSignal(0);

  return (
    <div>
      <p>Count: {count.value}</p>
      <button onClick$={$(() => count.value++)}>+1</button>
    </div>
  );
});

Core concepts:

• Resumability: Serialize listener registrations and state, resume without re-executing
• Fine-grained lazy loading: Each event handler is a separate chunk, loaded on interaction
• component$: Lazy-loadable component boundary
• $ suffix: Identifies lazy-loadable boundaries (events, stores, effects)
• Prefetching: Predicts user interactions and preloads handlers

// Qwik: code is split per-event by default
import { component$, useStore } from "@builder.io/qwik";

export const TodoApp = component$(() => {
  const state = useStore({ todos: [], filter: "all" });

  return (
    <div>
      <button onClick$={async () => {
        // This handler is a separate JS chunk
        // Only loaded when the user clicks this button
        const data = await fetch("/api/todos");
        state.todos = await data.json();
      }}>
        Load Todos
      </button>
      <TodoList todos={state.todos} />
      {/* TodoList component is also lazy-loaded */}
    </div>
  );
});

Strengths:

• Near-instant page loads (as low as 1KB of JavaScript)
• Automatic code splitting per event handler
• Best Core Web Vitals scores of any framework
• Scales to complex applications with no performance cliff
• Qwik City meta-framework with routing and data loading

Weaknesses:

• Most complex mental model of any framework
• $ suffix syntax can be confusing and easy to forget
• Smallest ecosystem and community
• Tooling and developer experience still maturing
• Resumability debugging is harder than traditional approaches

Performance Comparison

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