SSO

SSO (Single Sign-On) is an authentication scheme that lets a user sign in once and reach many independent applications without re-entering credentials for each one. Rather than every service holding its own username and password, SSO centralizes identity with a trusted provider and hands each application a verifiable assertion that the user is who they claim to be. It is what makes “log in with your work account” work across a whole suite of tools.

• Federated identity - A central identity provider vouches for the user to many relying applications, so trust and credentials live in one place.
• Standards-based - SSO is typically built on SAML, OpenID Connect, and OAuth 2.0 rather than a single proprietary protocol.
• Reduced credential sprawl - One strong, well-protected login replaces dozens of weaker passwords, shrinking the attack surface.
• Centralized policy and offboarding - Access, MFA requirements, and revocation are enforced in one control point, which matters enormously for security and compliance.

For API providers, SSO shows up on both sides of the house: it governs how developers and internal teams reach the developer portal and management consoles, and — through OpenID Connect and OAuth — it underpins how end users authorize applications to call APIs on their behalf. Identity platforms like Ping Identity and Kinde package this as a service, and as agents increasingly act for users, the SSO and token-issuance layer becomes the place where an organization decides what a machine identity is actually allowed to do.