Actually, I should clarify – I still remember the first time I tried to manually manage dependencies for a project with more than five files. It was 2014, and I was using jQuery. I spent six hours trying to figure out why undefined was not a function. Turns out, I loaded the script tags in the wrong order.

But fast forward to February 2026. Browsers support native ES modules. HTTP/3 is widespread. Internet speeds are faster. And here I am, staring at a terminal window waiting for a build process to finish, watching a bundler chew through 4,000 modules just so I can put a button on a screen. It feels redundant, right? But if you’ve ever tried shipping raw, unbundled ESM to production on a complex app, you know exactly why we’re still doing this. The waterfall network requests alone are enough to make Lighthouse cry.

There’s this persistent myth that bundlers are going away. “Browsers understand import now!” people shout on Twitter. But browsers are terrible at resolving deep dependency trees over a network.

The “Native ESM” Trap

Let’s look at a basic scenario. You want to fetch some user data and update the DOM. Simple stuff.

// api.js
export async function fetchUserData(userId) {
    const response = await fetch(https://api.example.com/users/${userId});
    if (!response.ok) throw new Error('Failed to fetch');
    return response.json();
}

// dom.js
export function updateProfile(user) {
    const profile = document.getElementById('profile');
    profile.innerHTML = 
        <h1>${user.name}</h1>
        <p>${user.bio}</p>
    ;
}

// main.js
import { fetchUserData } from './api.js';
import { updateProfile } from './dom.js';

(async () => {
    try {
        const user = await fetchUserData(123);
        updateProfile(user);
    } catch (err) {
        console.error("Something blew up:", err);
    }
})();

In a local dev environment, this works instantly. But in production? If api.js imports a utility library, which imports a validation library, which imports Lodash… your browser has to download, parse, and execute each file sequentially to find the next import statement. It’s a waterfall of latency.

The Rust Invasion: Rspack vs. The World

For the longest time, Webpack was the only serious game in town. But 2024 and 2025 changed things. We got greedy. We wanted faster builds. And we got tools written in Rust and Go.

I’ve been migrating a legacy dashboard from Webpack 5 to Rspack (the Rust-based Webpack compatible bundler). The difference is jarring. I’m running this on an M3 MacBook Pro, and the cold start time went from 45 seconds to roughly 3 seconds.

But speed isn’t everything. I hit a nasty snag with Rspack regarding custom loaders. If you’re using some obscure Babel plugin written in 2018 to handle a proprietary file format, good luck. The Rust bundlers are strict. They don’t have the decade of community patches that Webpack accumulated.

Code Splitting: The Real Superpower

The single most important job of a bundler in 2026 isn’t just smashing files together—it’s taking them apart intelligently. Code splitting is how we keep our initial bundle size under control.

Modern bundlers handle dynamic imports effortlessly. If you have a heavy charting library that only appears on one specific admin page, you shouldn’t ship it to every user.

// heavy-chart.js
export function renderChart(data) {
    // Imagine 200kb of D3.js logic here
    console.log("Rendering fancy chart with", data);
}

// main.js
document.getElementById('show-stats').addEventListener('click', async () => {
    const container = document.getElementById('chart-container');
    container.innerText = "Loading module...";
    
    try {
        // The bundler sees this and creates a separate chunk automatically
        const { renderChart } = await import('./heavy-chart.js');
        
        const data = [10, 20, 30, 40];
        renderChart(data);
    } catch (error) {
        container.innerText = "Failed to load the chart module.";
        console.error(error);
    }
});

A Real-World Benchmark: Vite vs. Rspack

I was skeptical about the hype around the newer Rust-based tools. I mean, Vite is already fast enough, right? So I decided to actually measure it instead of just reading Reddit threads.

• Vite 6.1 Build Time: 14.2 seconds
• Rspack 1.1 Build Time: 2.8 seconds

That’s nearly 5x faster. However, the bundle size was slightly larger with Rspack (about 4% bigger). Rollup’s tree-shaking is still the gold standard for squeezing every last byte out of a bundle. If I’m building a library where every kilobyte matters, I’m sticking with Vite/Rollup. But if I’m building a massive enterprise app where dev speed is the bottleneck, Rspack wins.

The Configuration Nightmare

Let’s be real: nobody actually likes writing configuration files. We copy-paste them from Stack Overflow or old projects. But you need to understand what’s happening.

Here’s a “gotcha” that bit me recently. I was using a dynamic import with a variable path in Vite.

// This works in Webpack but can be tricky in Vite
const locale = 'en-US';
const messages = await import(./locales/${locale}.js);

Vite (and Rollup) needs to know which files could match that pattern so it can bundle them all. If your variable is too generic (like import(path)), the bundler has no idea what to include and will likely throw a warning or break at runtime.

So, What Should You Use?

Use Vite. The ecosystem is massive, the plugins work, and it’s fast enough for 99% of use cases. It’s the safe, boring choice, and in software engineering, boring is good.

Look at Rspack if you are migrating a massive Webpack codebase and can’t afford a complete rewrite, or if your build times are literally slowing down your team’s velocity. But check your plugin compatibility first.

Avoid Webpack for greenfield projects. I have a lot of respect for what Webpack did for the web, but the config overhead is just too high compared to the zero-config defaults we have now.

Bundlers aren’t going anywhere. They’re just getting faster, smarter, and thankfully, more invisible. Now, if only they could fix my CSS dependency graph, I’d be a happy developer.