Yes
Wix supports a mulitude of APIs to used for various fetch calls for your web pages.
If you already have to API's in mind you can venture off within you WIX code to integrate within your application's processes.
There shouldn't be any complications getting this done.
Please see the link below for more information

https://www.wix.com/code/home/api

Yes, it's possible please visit the below post for accessing third party services and information about api in wix.
https://support.wix.com/en/article/corvid-accessing-third-party-services-with-the-fetch-api