Micro Frontends

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Chris Coyier on (Updated on )

One random day not long ago, I started hearing joke after joke about “micro frontends” — sort of how I first learned about Toast. I didn’t understand the source until asking around, which uncovered this article from Cam Jackson.

In this article we’ll describe a recent trend of breaking up frontend monoliths into many smaller, more manageable pieces, and how this architecture can increase the effectiveness and efficiency of teams working on frontend code.

I’d argue it should read “front-end monoliths” and “front-end code,” but I digress already.

The idea is similar to microservices, but for the front end. So, instead of one big front-end architecture (e.g. a React app), different parts of the front end are developed entirely independent of one another, have no dependencies on each other, and can be worked on and deployed independently.

It’s one of those things where you can’t quite tell if it’s really an interesting foretelling of the future, just a niche architectural choice that happened to work for a handful of large organizations, or even just a theoretical option.

The first place my mind goes is consistency and DRY-ness. Anywhere I’ve worked, these things are a big deal and it seems like the industry at large has had endless front-end problems with shipping designs that start and stay consistent and cohesive without repeating itself with shovelfuls of technical debt. Independent front-ends sound like they might be a problem if Team B is being blocked by Team A for something not directly related, but then it introduces the problem of Team B’s output drifting towards inconsistency with Team A’s output.

The article itself talks about a browse/search landing page, a details/ordering page, and a profile page, with all three of those tackled by different independent products/teams. It sounds kinda cool and interesting to me, and it also sounds like those teams better sit right next to each other at work; otherwise this app is going the way of Frankenstein’s monster in two weeks. Styling is only lightly addressed with a, “I dunno, do a good job” sort of vibe. Teams struggle with this when they are all on the same product, so I’d have huge concerns here. The first thing I’d try to solve if this is being discussed seriously would be a design system that transcends all of it and that everyone uses without fail.

And what if those micro front ends co-exist on the same page? Use <iframe>, the article says. I can’t see a world where that leads to a good user experience. (iFrames are slow, especially many of them all booting up their own worlds — and what about elements that might overflow bounds like tooltips and menus?)

The other integration options… isolating them to their own bundles or even native web components sounds a bit better. But still, the idea of siloed development where a React component might be slapped on the same page as a Vuew component seems like a huge user penalty for a pretty specific organizational problem. Not to mention you’re losing the benefits of a shared understanding of a codebase and the benefits of a deeper technical understanding of a smaller set of tools.

I’m probably not characterizing all of this fairly, especially because the idea is rather new to me and I’ve never worked like this before.

Nader Dabit has a follow up article: Building Micro Frontends with React, Vue, and Single-spa. Just so I’m not mischaracterizing that: The idea really is that you might build a React app and I build a Vue app and we’ll slap ’em together on the same page. I definitely come from an era where we laughed-then-winced when we found sites that used multiple versions of jQuery on the same page, plus one thing that loaded all of MooTools and Prototype thrown on there seemingly by accident. We winced because that was a bucket full of JavaScript, mostly duplicated for no reason, causing bugs and slowing down the page. This doesn’t seem all that much different.

Joel Denning points out in an AMA on the subject:

I’m pointing out that we’re in the “hate without closely examining” stage of the idea. It’s entirely possible that after legitimate, close examination that the idea still fails. But too early to tell.

Fair enough.

Sorry about piling on. 😣