First of all and foremost, there are 2 schools of thoughts about how a micro-frontend should look like, as explained in the previous article where I was explained different implementations of micro-frontends, there are implementations where a micro-frontend correspond to an area of the user interface, others where the micro-frontend is a SPA or a single page.
When we consider the micro-frontends implementation based on different logical areas of the application (like a header, a footer, a payment form and so on) we would face different challenges like:
Which team would assemble the aggregated view?
How can we avoid external dependencies in every team?
Which team is accountable for an issue in the aggregated view?
How do we ensure that a specific area of the application is not tightly coupled with the parent container?
How can we be sure there aren’t conflicts between dependencies?
Are we assembling at runtime or compile time?
If we decide to create the page at runtime time, is our application servers layer scalable?
Is the content cachable and for how long?
How do we ensure the development flow is not impacted by distributed teams?
And many other questions (technical and organisational) that could make our life way more complicated than how it could be.
Interestingly enough, this approach didn’t provide the expected benefits for Spotify working at scale and they reverted back to a more “classic” architecture based on SPA.
For the benefits of this post, let’s define our micro-frontends as SPA or single pages with a generation made at compile time in order to avoid any possible surprise happening at the composition layer.
Anyway, there are some challenges to face also with this approach, probably the main one is understanding how we want to orchestrate our micro-frontends and it is the focus of this post.
The orchestrator layer could be either on the client-side, server-side or edge-side; the solution depends on how “smart” the orchestrator layer should look like for our applications.