How to get wopi discovery in the host page

I'm working on an Office integration for the web using WOPI and trying to get the WOPI action from discovery.

I know the dogfood/testing endpoint from where I can get the discovery. But I couldn't directly get it in my web app due to cross-origin issue as it is in a different domain.

Am I supposed to store the discovery in API and serve it to the web app?

Answering for the readers.

I was checking with Microsoft Senior Program Manager, he confirmed that WOPI discovery is meant to be a server-server thing. We need to fetch the WOPI discovery in the API side and keep it in cache until the proof key validation fails.