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If you're working with web applications or cloud-based services, you've likely come across the acronyms SAML and SSO. Both technologies are essential in managing user authentication and access control but differ in how they handle the process.
Comparing SAML and SSO can be confusing, as they’re closely related. Together, they offer a secure means for users to employ a single set of credentials to log in to multiple applications. Doing so simplifies the authentication experience, enhances security, and helps prevent account takeover.
In this article, we'll take a closer look at SAML vs. SSO to help you understand the differences and similarities between these two terms.
Single sign-on (SSO) is a simplified login experience that uses a single set of credentials across multiple apps; Security Assertion Markup Language (SAML) is a protocol that makes SSO possible.
SAML and SSO often go hand in hand, but they can also exist independently. SAML can secure a single enterprise app, while SSO can run on OIDC, passkeys, or magic links without SAML.
Other protocols that can replace SAML in the SSO process include OIDC and passwordless authentication methods.
What is SSO?
Digital service providers (SP) often offer multiple related applications in their suites. For instance, they may have separate platforms for:
Email
Maps
Conferencing
Cloud storage
Video sharing
Web browsing
Calendar services
Single sign-on (SSO) is an authentication method that uses a singular set of credentials (like a username and password) to log in to all of these related services. If you’ve used Maps, Gmail and Drive with your singular Google account, you’ve already experienced the benefits of SSO.
When a user logs in to an app through an SSO entry point, their identity is confirmed across all related applications. Hence, they don’t need to re-enter their credentials to access other services. This allows employees to seamlessly bounce around an organization’s digital platforms and users to switch apps effortlessly.
To that end, SSO reduces the likelihood of account takeover. But that’s not its only benefit – fewer credentials also means fewer passwords for cybercriminals to steal. This, in turn, leads to a more secure authentication process for users.
How does SSO work?
SSO works by having a single trusted login system confirm user identity one time. It then reuses the login across multiple apps, so users don’t have to input their credentials again. Practically speaking, the auth flow looks something like this:
The user attempts to open an app (e.g. Slack, GitHub)
The app redirects the user to a login provider (e.g. Microsoft, Okta)
The user logs in with their credentials (or a passwordless authentication method)
The identity provider (IdP) checks these credentials and confirms identity
The user gains access to the original app
The next connected app checks the existing SSO session and allows access without prompting for credentials again.
What is SAML?
SAML stands for Security Assertion Markup Language. It’s an Extensible Markup Language (XML) standard that facilitates secure authentication and authorization data exchange. XML standards function like rules in any other language, dictating how to make sense of things. In this case, SAML makes sense of packages of data.
SAML is like a secret code that allows SSO to work. It helps online services communicate with identity providers (IdPs) to confirm user credentials.
Essentially, most applications defer user authentication to a third-party IdP. But SAML provides the guidelines for the application's login interface to safely and intelligibly exchange information with the IdP. This means the user’s identity can be confirmed quickly and securely.
In other words, when you log in to an SSO system, SAML helps prove that you are who you say you are and that you’re allowed access to authorized websites and applications.
How does SAML authentication work?
Here’s what happens behind the scenes when users engage with a SAML-powered SSO system:
The user tries to open an app
The app redirects the user to an IdP for login
The user authenticates themselves with the IdP (using a password, MFA, etc.)
The IdP creates a signed SAML assertion (i.e. proof of identity) in XML
The app receives this assertion, validates the signature, and gives the user access
Although SAML is a popular protocol for SSO, it’s not the only one. Newer systems often use OpenID Connect (OIDC) for its lightweight, mobile-friendly qualities.
Further Reading: OIDC vs. SAML: Understanding the Differences
The difference between SAML and SSO
Since they’re both aspects of the same authentication process, it’s easy to confuse SAML and SSO. However, while they’re related, they’re not the same.
SAML | SSO | |
|---|---|---|
Purpose | SAML is the standard through which SPs and IdPs communicate with each other to verify credentials. | SSO is an authentication process intended to simplify access to multiple applications with a single set of credentials. |
Features | SAML improves security by unburdening SPs from having to store login credentials. Instead, it places the responsibility on IdPs that specialize in such services. | SSO simplifies user experience (UX) by providing a singular access point for the multiple services and platforms users regularly access. |
Use cases | SAML simplifies and controls authentication-related tasks. It enforces secure login protocols and manages authentication permissions across various platforms. | SSO enables integrated logins across an organization’s multiple services, reducing credential fatigue and support overhead. |
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SAML and SSO are often seen together, but it’s possible to encounter one without the other. For example, SAML can be used as the login protocol for a single enterprise app without being connected to an SSO system. Meanwhile, SSO can be powered by other protocols, such as OIDC, or passwordless methods, like passkeys and magic links.
How SAML and SSO are related
SAML is one of the many standard protocols that can be used to power SSO authentication. While SSO logs users in to multiple accounts with a single set of credentials, SAML is one of the rulebooks that mediates how to authenticate such login requests.
Employing SSO facilitates simple user login for organizations, businesses, and developers seeking to deliver better UX across their digital services.
Implement SAML-based SSO authentication with Descope
SAML is one of the industry-standard protocols for facilitating a smooth, secure SSO experience. Together, SSO and SAML protect users from unauthorized account access, without sacrificing convenience. However, poring over the intricacies of the SAML protocol can be complex and time-consuming.
To keep logins simple and save time for developers, give users a single authentication solution across all your platforms with Descope’s SAML-based SSO. Descope's visual workflow editor lets developers implement SAML-based SSO without hand-coding protocol logic or maintaining IdP integrations, freeing up engineering time for product work.
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