(Security Assertion Markup Language) Standard for single sign-on. SAML (pronounced 'sam-ul') defines the format of XML messages that applications can use to exchange information about network identities and access rights. Messages are passed over a secure HTTP connection, normally in SOAP format. The main benefit of SAML is 'single sign-on' (sometimes abbreviated to SSO), whereby a user's network identity and/or access rights can be passed from one web service or application to another without the user having to re-enter them each time.