To this day automated tests suits against UI tends to be flaky. So testing against a code api is indeed better. Most of this stuff is just developing against i

To this day automated tests suits against UI tends to be flaky. So testing against a code api is indeed better. Most of this stuff is just developing against interfaces, and having that interface owned by the business code. All infrastructure code implements those interfaces. Business code code doesn't get polluted by technical infrastructure stuff. It's easy swap out databases, etc Always a good idea. Functional core, imperative shell is also a modern term for this.