I'm developing an input limited device that has no web browser, no fixed IP, no fixed URL, and no keyboard, but can access the internet and display information.How does the device get a token to call the gmail API and read gmail?

I want to read gmail on input-limited devices witch not have web browser.I get token following https://developers.google.com/identity/protocols/oauth2 , but they need redirect uri or not support gmail scope.I don't have a website on the internet ,so ...