Connection between Wix Stores and my stock inventory using WebApi

Hi there! I’m facing with the following problem:
I need to connect Wix Store with my existing inventory using the WebApi and I really don’t know where to start… did anyone faced with the same problem? Can anyone help me?

https://support.wix.com/en/article/corvid-accessing-third-party-services-with-the-fetch-api
https://support.wix.com/en/article/corvid-calling-server-side-code-from-the-front-end-with-web-modules
https://www.wix.com/corvid/reference/wix-http-functions.html
https://support.wix.com/en/article/corvid-exposing-a-site-api-with-http-functions

I’m interested in hearing responses. Eventually I will have to support various inventory APIs. May I ask whose Inventory system are you using? Do they publish their API?