Security Assertion Markup Language (SAML) is an open standard that allows identity providers (IdP) to pass authorization credentials to service providers (SP). ... SAML is the link between the authentication of a user's identity and the authorization to use a service.

Is SAML a protocol or framework?

SAML is an XML-based markup language for security assertions (statements that service providers use to make access-control decisions). SAML is also: A set of XML-based protocol messages. A set of protocol message bindings.

Where is SAML used?

SAML - Most commonly used by businesses to allow their users to access services they pay for. Salesforce, Gmail, Box and Expensify are all examples of service providers an employee would gain access to after a SAML login. SAML asserts to the service provider who the user is; this is authentication.