Open the offerwall without an SDK

If you cannot use a native SDK, create an offerwall URL on your server for the signed-in user and open it in the device browser. Use the UID generation guide to build https://www.rapidoreach.com/ofw/?userId=... without exposing your App Key in the app.

// url comes from your authenticated backend for the current user.
startActivity(Intent(Intent.ACTION_VIEW, Uri.parse(url)))

// urlString comes from your authenticated backend for the current user.
if let url = URL(string: urlString) {
    UIApplication.shared.open(url)
}

Do not let the client choose another user's ID when requesting the URL. Set up a server-to-server reward callback and use the testing checklist before launch. The browser returning to your app does not prove that a reward was earned.