Single sign-on (SSO) is an authentication method that enables users to access multiple applications with one login and one set of credentials4. There are two types of SSO flows thatcan be used with Salesforce as the service provider (SP) and an external identity provider(IdP)5:

Service-provider-initiated SSO: The user requests a resource from the SP, such as a Salesforce URL. The SP redirects the user to the IdP for authentication. The IdP authenticates the user and sends a SAML response to the SP. The SP validates the SAML response and grants access to the user5. This type of SSO flowsupports deep linking, which means that the user can access a specific page within Salesforce without logging in again6.

Identity-provider-initiated SSO: The user logs in to the IdP and selects an app from a list of available apps. The IdP sends a SAML response to the SP. The SP validates the SAML response and grants access to the user5. This type of SSO flow does not support deep linking, which means that the user can only access the default landing page of Salesforce6.