App passwords (sometimes called "app-specific passwords") are randomly generated passwords that provide a secure way for end-users to authenticate with third parties such as Nylas, without using their regular account password.
Because every provider has a different way of creating an app password, you must direct your end user to their provider's app password tool so they can create one. When that's done, they can complete the authentication process with Nylas.
When you use the detect provider endpoint, Nylas includes a link to the detected provider's app password tool, if one is available.
An app password is required if 2FA is enabled and you are authenticating without a security code.
Yahoo Mail accounts require an app password for Nylas to authenticate. An app password gives Nylas access to the account through the single password login.
Apple ID uses an app password for accessing information in iCloud.
The following providers also require app passwords: