I'm mostly Frontend developer recently so I haven't been much up to date with Backend technologies. If I need a CMS for my frontend, what technology(-ies) can I use?
I'd go with Ruby on Rails if it's mostly CRUD operations. You'll be very quick to get something up and running to power your frontend.
You could also use some hosted services like https://firebase.google.com / https://www.contentful.com but that depends on your use case and if you want to be dependent on someone in return for being a bit faster.
You could also use some hosted services like https://firebase.google.com / https://www.contentful.com but that depends on your use case and if you want to be dependent on someone in return for being a bit faster.