GitLab CI for monorepo

Hello, I am currently using GitHub but I am using GitLab at work and given its nice features I am thinking of moving everything here.
I am interested in using GitLab CI, but I need to know first if it would be possible for me to configure it so that my monorepo will be built entirely:

I need to test and build client, landing and api (it should make a docker image and push it to docker registry).
Is it easy and doable or more like a PITA?