Hey Ruben, Thanks for your quick reply!
I think the flow you’re describing uses a web browser since `/authorize’ should get the user to the login page. but in this case we need to use the App native UI (No web browser).
I found this post Passwordless with React Native and Auth0 which pass the code_challenge in the passwordless/start endpoint but the official api documentation does not include those params.
Also when checking at the source of react-native-auth0 I see no PKCE methods are being used when passwordlesswithSMS function is executed. react-native-auth0/index.js at master · auth0/react-native-auth0 · GitHub
I’m a bit lost here since the documentation and the examples I’ve found are conflictive. I appreciate any clarification 
To clarify the scenario:
- Using auth0 vía API’s from the device (Not the SDK)
- In react native, without any web-browser view.
- using Passwordless SMS/OTP.