Chapter 6

1. As an SPA is running in the browser, it cannot use a confidential client directly, which results in a greater risk if a refresh token is leaked. For this reason, it is more secure to have a backend running in a web server that can use a confidential client and store tokens on the server side.
2. No, any type of application can use OAuth 2.0 through an external user agent to obtain an access token, and many different types of services have support for bearer tokens.
3. An application should never collect user credentials directly as this increases the chance of credentials being leaked, and provides the application with full access to the user account. For this reason, native and mobile applications should use an external user agent to authenticate with Keycloak.