Using both API and Webview in mobile app, can you prevent logging in twice?

I’m currently working to integrate Discourse into an existing iOS and Android app. The plan was to utilize the existing Discourse website for browsing, but use the API for for post creation, since I have a number of app related fields which I would like to pre-populate on a post. I don’t have much experience with web development, so this is mostly new to me so learning as I go here.

I was able to login and generate an API key via the API, and my thought (which in reflection I now realize didn’t make any sense at all), was that using this method would enable also share the session with the webview and allow that to be logged in.

This isnt the case obviously, I seem to be able to do everything I would expect but I have to login twice, once via the API and once via the webview. Is there anyway to simplify this, and allow for a single login to authenticate both the webview and allow for API access?