It definitely is, and it's supported natively as of Mendix version 7.10.0
Take a look at the documentation here for published rest services.
which contains this handy introduction/howto video https://www.youtube.com/watch?v=HzrFkv0U4n8
Here's the link for consuming rest services natively in Mendix.
Edit: seems we all responded within the same minute haha.
Yes indeed! Mendix supports the creation of REST services out of the box. Here is a how-to guide that will help you publish REST services in Mendix.
For guided tutorials on consuming and publishing REST services, check out the 'Importing and Exporting Data' learning path from our free academy!
There is a learning path https://gettingstarted.mendixcloud.com/link/path/33
The advantage is not only that with dragging and dropping from your domain model you can model your api pretty easily and faster than coding, it has also the advantage that the mapping inmediately refers to entities in your domain model. Hence making it easier to map the data to the correct tables. Next to this it's easier for others to understand which only model and do not code.