The Labproof over claims.

Proof over claims. Every number below is measured live on this page, in your browser. Not screenshotted from a framework's documentation.

Core Web Vitals captured from this very page while you read it.

LCP

measuring…

measuring…

INP

measuring…

measuring…

CLS

measuring…

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JS loaded

0 KB

good

The counter ticks up only when you interact with a module below.

LAB-01status:live

Live Patch Grid

400-node fine-grained reactivity, head to head with a simulated VDOM re-render.

0/s
1nodes updated / interaction
0updates / sec
0patches
updates / sec

One interaction, one node. The grid stays responsive while the patch counter climbs.

Why it matters

In a VDOM world, one hover reconciles all 400 nodes. Here it touches exactly one. The same reason this page ships almost no JavaScript.

Glide the cursor. Qwik tracks reads through proxies and patches only the cell you touched.

LAB-02status:live

Animation Bench A/B

Compositor-thread vs main-thread animation, running side by side.

0 FPS
WAAPI · compositorGPU
Signal · main threadJS
0avg FPS
-longest frame
-long tasks
FPS history

Why it matters

Animating transform and opacity on the compositor thread is how interfaces stay responsive under load. That is also how I debug jank when a client reports it.

Both engines run 350 particles. Only one of them can starve the main thread.

LAB-03status:live

Deferred Compute

Heavy logic that costs nothing until it is invoked.

0 KB

Heavy chunk awaiting request

This module's JavaScript has not been downloaded yet. Activate it and watch the network.

0 KBInitial paint JS
-On interaction
-Hydration + compute

This page (measured)

Initial paint JS0 KB
On interaction0 KB

Why it matters

This is why pages I build can render in under a second even with heavy logic. The heavy code simply is not on the page until it must be.

A Mandelbrot renderer runs inside a Web Worker. Its chunk is requested only when you press the button.

LAB-04status:live

Code Review Arena

A component generated by an AI model, with six production bugs hiding in it. Find them, then read my review.

The AI Output

Prompt: "Build a searchable product table for 10,000 rows." This is the unfiltered result.

ProductTable.tsx53 lines
import { useState } from "react";

const ProductRow = ({ product, i }) => {
  return (
    <tr key={i}>
      <td>{product.name}</td>
      <td>{product.sku}</td>
      <td>{product.price}</td>
      <td>{product.stock}</td>
      <td>
        <button
          className="icon-btn"
          aria-label="Edit"
          onClick={() => editProduct(product)}
        />
      </td>
    </tr>
  );
};

export default function ProductTable() {
  const [query, setQuery] = useState("");
  const [products, setProducts] = useState([]);

  const filtered = products.filter((p) =>
    p.name.toLowerCase().includes(query.toLowerCase())
  );

  const search = (value) => {
    setQuery(value);
    fetch("/api/products?q=" + value)
      .then((res) => res.json())
      .then(setProducts);
  };

  return (
    <div className="table-wrap">
      <input
        placeholder="Search products..."
        value={query}
        onChange={(e) => search(e.target.value)}
      />
      <p>{filtered.length} results</p>
      <table>
        <tbody>
          {filtered.map((product, i) => (
            <ProductRow key={i} product={product} i={i} />
          ))}
        </tbody>
      </table>
    </div>
  );
}

What did you spot?

Why it matters

Generating code is commoditised. Reviewing it (performance, accessibility, edge cases) is the job.

Every fix below is the kind of comment a senior engineer leaves in a pull request.

LAB-05status:live

Bundle Budget

What this page really shipped. Measured from network, not estimated.

0 KB

This page (measured)

0 KB
…

Classic SPA baseline

react + react-dom~49 KB gzip
react-router-dom~13 KB gzip
Total~62 KB gzip

Public numbers from framework documentation, not measured here.

A classic SPA ships its framework up front, about 62 KB gzipped before any interaction. This page ships its application code only when you interact.

Why it matters

Every kilobyte of JavaScript is parse cost on someone's phone. Budgets turn that intuition into a number.

The resource list updates live as chunks load.

Every demo above is this page.

Reactivity, animation, deferred loading, code review. All of it runs on the site you are looking at, with no third-party JavaScript.