Your Guide to Architectural Decisions in Enterprise Development with Module Federation

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Introduction

Every now and then questions about Module Federation pop up in social media:

“Why should I use Module Federation?”
“What is the benefit of Module Federation? I use Next.js and it works fine!”
“I do not understand how Module Federation should help me in our project?”
“why do you need Module Federation when you can use iframes instead?”

First of all, it’s essential to get some misconceptions out of the way. Module Federation is not a replacement for any specific technology stack. By default, it is technology-agnostic. To understand what Module Federation is we have to see it as an architectural pattern designed to orchestrate and manage code in a decentralized manner.

Let’s embark on a journey

Let us dive into the topic by starting a new project. We will explore a small architectural decision tree by addressing a series of key questions.

Let’s start with some fundamental architectural questions:

What is the size of your project?
Is the project supposed to scale and grow over time?
Will the project function as a standalone application, or is it part of a larger customer-facing system or platform?
How does the application relate to other applications within the ecosystem?
Will you need to integrate or inject other applications into your own?
Are you collaborating with other teams, and if so, how interconnected are your applications?

Scenario 1:

If your project leans toward a more isolated environment with minimal dependencies and limited to no communication with other teams or applications, go with a standalone Single Page Application (SPA) or Multi Page Application (MPA). This approach has the smallest complexity footprint in system architecture and will be sufficient for your use-case.

Scenario 2:

In contrast, if your project leans towards a more interconnected application that is part of a larger customer-facing platform, your requirements will differ significantly. Topics such as shared data, robust cross-application event messaging, third-party component integration, shared libraries, overlapping customer journeys and use-cases may sound familiar to you. In such a scenario, relying on a traditional Single Page Application (SPA) or Multi Page Application (MPA) architecture will lead to challenges in terms of scalability and governance, eventually.

What’s the solution? In my opinion, there are two viable approaches. The next questions you should consider are the follwing:

Is my team or department responsible for all surrounding applications (top-level-domain ownership)?
If overlapping features arise, how quickly and easily can we align and execute across applications? (Often, challenges stem from mismatched business processes, expectation management, or operational modes)
To what extent can we establish control, influence, guardrails, and governance for all connected applications from an architectural perspective?
How tightly or loosely coupled are the interfaces with other applications?

Scenario 1:

Do you lean toward a controlled, self-owned environment with aligned processes, cohesive teams, and a shared architecture that reflects matching business processes? Ideally, you would manage and orchestrate your environment using a controlled monorepo approach. The go-to option to realise this is Nx: Smart Monorepos. Nx significantly enhances your ability to scale and adapt to unforeseen changes within the system in the long term. This makes it an invaluable asset in your ecosystem.

You made it until here. Finally we can face the elephant in the room. When to use Module Federation?

Scenario 2:

If your situation involves decentralized teams with limited touchpoints and mismatched business processes, where sharing modules is only possible by using the dreaded Iframe injection of uncontrolled sources, and there is no clear definition of the interface for application communication, then Module Federation is the system architecture golden nugget you were searching for.

Benefits of Module Federation

The lack of governance and control over decentralized dependencies can become a long-term challenge and will haunt you, ultimately leading to one of the most dreaded outcomes in architecture land… Responsibility for code you do now own.

So why is Module Federation so good for these use-cases?

Imagine you are working in an enterprise-grade company that serves around 30 customer-facing applications. The application you’re developing features a really cool Header component, which includes a Main Navigation, a Search bar, and a nifty User Account Widget. However, the new corporate strategy wants all customer-facing applications to maintain a consistent look and feel to create a cohesive customer journey.

The simplest solution is to throw the Header in a component library hosted on npm or Artifactory, allowing all applications to utilize it seamlessly. Unfortunately, the reality is more complex. A common challenge when sharing code through packages in an interconnected environment is the cascade of events triggered by changes, which can significantly complicate the development process. In the worst-case scenario, this can severely throttle your team’s velocity. Let’s check what this cascade of events may look like:

Your team needs to update the Header component.
Your team must deploy a new version of the component to npm or Artifactory and update the dependencies of your applications.
Your team has to communicate with other teams to inform them of the available update.
The other 30 teams must plan the request in their development cycle.
Each of the 30 teams needs to update their npm dependencies and deploy their changes according to their release cycles.
Your team must coordinate their release cycle with the other teams and deploy the update as well.
Finally, all customers see the update and are happy… BUT your company wasted a tremendous amount of money on sync meetings, dependency updates, release cycle alignments across different teams and some development time.

This scenario is commonly known as “Double Deploy Syndrom” and you definitely want to avoid it. With Module Federation this process is obsolete. The cascade of event looks like this:

Your team needs to update the Header component.
After the CI chain is complete, all consuming applications reload their page and the updates are fetched automatically with the correct version applied.
Embrace this magic moment.
That frees up development resources, follows a clean separation of concern directive, leads to cost effectivity and removes unwanted responsibilities and dependencies of teams.

This architectural approach introduces the following benefits:

It frees up a lot of development resources
All connected applications are more orthognal by design
All connected applications have a clean separation of concern
Immediate cost effectivity
Removal of unwanted coupling and responsibilities to other teams.

The described example is by far the most distruptive alteration in enterprise development with the biggest magnitude for your development teams as well as the overall workflow of your business. Nevertheless, it is just one of many interesting use-cases where Module Federation can add benefit to projects and companies.

Nx with Module Federation

Before I share my final thoughts, there is one topic I want to address specifically: Nx monorepos in combination with Module Fedearation. Nx is exceptional for orchestrating and managing your applications, particularly within complex enterprise-level structures. Utilizing Nx monorepos can significantly streamline your infrastructural efforts. I highly recommend using Nx monorepos in combinationwith Module Federation, as this combination will enable your teams to be more efficient and adaptable when larger changes are introduced to your platform.

Key Insights on Module Federation for Business Leaders

For those who find the previous content too technical, here is the TL:DR of why Module Federation is a good solution for Enterprise level Development.

Module Federation offers a powerful solution for organizations with highly decentralized teams, enabling seamless and consistent customer journeys with minimal touchpoints between development teams. By streamlining the deployment process, it significantly reduces time-to-market on frontend side, eliminating the need for double deployments and minimizing synchronization efforts across teams.
With features such as fallback rendering, error boundaries, proxy layers, and static TypeScript types, Module Federation enhances platform stability, outperforming traditional methods like iframes.
This architectural pattern is particularly well-suited for large-scale, omnichannel systems that require ongoing growth and the ability to scale both horizontally and vertically. Embracing Module Federation can position your organization for greater agility and resilience in a rapidly evolving market.

Final Thoughts

After working quite a while with Module Federation it is not just an architecture pattern like mentioned in the beginning. It is a disruptive shift in development mentality. Module Federation unlocks a wide array of new use cases and enhances interconnectivity between content-providing and content-consuming applications. It functions like iframe technology on steroids, offering features such as shared static TypeScript types, Error Boundaries, Dynamic Proxying, Runtime Hooks, Shared Dependencies, and even opt-in solutions for prefetching modules within a Server-Side Rendering (SSR) environment.

I hope I was able to clarify some aspects of the often-confusing debate surrounding Module Federation. It is a complex topic that requires a certain investment of time and effort to fully understand and appreciate but the invest will pay-off, I promise. If not, at least I hope this article sparked your curiosity about new ways of working with web-technologies.

Useful Links

(If you did not yet decide which bundler to use — Rsbuild is the best suited companion when working with Module Federation)

Modern.js

(If you need first-class support for Module Federation in a Multi-Page-Application scenario with Module Federation Server Side Streaming — Modern.js is based on Rspack and delivers exceptional DX for enterprise Microfrontend architectures)