if you are only handling public data, you can have you app call a backend server and the backend server calls Twitch using an App Access Token
If it’s “private data”
Given that step one of oAuth is to redirect a user to a website, then you need to open a webview in order to load the Twitch Website. And come back to you, via implicit auth.
The alternative is you have an accounts system on your server, then your app can login to the server via whatever method.
And you can use a Web Browser to link the server account with a Twitch/anyOtherService account.
So when you app logs into the server it looks up the logged in users linked Twitch account
Didn’t know that was against the app stores. I’m looking at apps in the short term and this surprises me