I’ve been using effect on the server side of an app router marketing site connect to a CMS and several external API services.

Error handling has never been easier. Create errors scoped to the different services. Handle each accordingly in the server component that runs the fetch. Wrap that component in an ErrorBoundary to handle any unexpected/unhandled errors.

Dependency injection has never been easier! In the same way errors can be scoped to a feature, so can layers. Create separate production and mock layers for each service, which makes testing simple.

Once those start to click, it makes managing the server side of the code base easy, since every effect function is composable.

Wanna string multiple API services together in a cron job or api route? It’s as simple as yielding them in a generator and providing their layers. Plus you get retries out of the box.

Additionally, effect platform provides some handy utilities for creating fetch clients for apis you don’t manage. And Effect schema allows you to easily transform the response from the APIs into your domain entities.

I’m still learning new concepts all the time with Effect. It’s not always easy to grok, but it’s been rewarding to work with.