"Distributed" micro-frontends

[romainl]

I've been working on a rather large e-commerce project and the pattern we chose for our micro-frontends is a bit different from the vertical pattern you describe.

Basically, we have:

• a (growing) number of strictly back-end microservices handling everything from querying the user repository to synchronizing our data with the legacy system,
• a (growing) number of strictly front-end microservices handling, well… the front-end aspects.

Part of our reasoning comes from the fact that we are transitioning from a monolithic legacy system to a microservices-based system and that transition implies different lifecycles for our back-end services and our front-end services. It's a lot easier for the latter to reach a stable "target" state, but the former will have to go through more evolution to reach that state. By decoupling the micro-frontends and the "micro-backends" (we don't call them like this, actually, but it seems to describe them quite well) we allow them to live separate lives and be deployed separately, in a more "atomic" manner.

Technically speaking, our micro-frontends are made of:

• a Spring Boot/Cloud application whose job is limited to registering the micro-frontend into the whole system, serving assets, and reverse-proxying request from the front-end to various "micro-backends",
• a React application that only knows how to query stuff within the micro-frontend itself.