An identity provider is the system responsible for authenticating a user and issuing a token or assertion that other applications trust as proof of that authentication. In a single sign-on architecture, the IdP is the central authority every connected application relies on rather than authenticating users itself.
Frequently asked questions
Can a business have more than one identity provider?
Yes, and it's common for a business to act as its own IdP for customers while federating with external IdPs for enterprise B2B customers or social login.
What's the difference between an IdP and a service provider (SP)?
The IdP authenticates the user and issues the assertion; the SP is the application that trusts and consumes that assertion.
Does the IdP concept apply to AI agents?
Yes, the same IdP issues the OAuth access tokens an agent presents to a protected resource, just with agent-specific scopes and consent attached.
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