OIDC vs. SAML: Key differences & how to choose

Pop quiz: What do your HR system, CRM, and expense tracking app have in common? Besides being essential to running your business, they all store sensitive data. Data that needs to be protected from unauthorized access.

But in today's world of remote work and cloud-based everything, the old "one password per app" approach just doesn't cut it anymore. Employees are overwhelmed, IT is struggling to keep up, and hackers are having a field day.

Enter OIDC and SAML—two authentication protocols that can help you secure access to all your apps and services, while still providing a seamless login experience for users. In this article, we'll break down what these standards are, how they work, and how to choose the right one for your specific needs.

What is OIDC (OpenID Connect)?

OpenID Connect, commonly known as OIDC, is an authentication protocol that allows applications to verify a user's identity using information from an authorization server. It extends OAuth 2.0 by adding an authentication layer, enabling identity verification along with authorization, and uses JSON web tokens (JWTs) to securely transmit user info.

With OIDC, users can log into multiple applications using a single set of credentials managed by a trusted identity provider (IdP). That IdP conducts the actual authentication—verifying the user is who they claim to be. It then sends identity information to the application to authorize access. This decoupling of authentication from individual apps is known as federated identity.

The key components of OIDC are:

• User: The person attempting to access an application
• Relying party (RP): The application or service the user wants to access
• OpenID provider (OP): The authorization server that authenticates the end-user's identity and issues access tokens to the RP
• ID token: A JWT that contains claims about the authenticated user
• UserInfo endpoint: An OP endpoint that returns claims about the authenticated user

By outsourcing authentication to a trusted OP, RPs can provide a streamlined login experience without having to manage user credentials themselves. And users get the convenience of single sign-on (SSO), logging in once to access multiple apps.

How does OIDC work?

OIDC authentication flows can get quite complex. At a high level, the process works like this:

1. A user tries to access a protected resource (like an app) from a client device
2. The RP sends an authentication request to the OP, specifying the desired scope (the level of access requested) and other parameters as needed, such as the response type or redirect URI  
3. The OP authenticates the user (via login page, MFA prompt, etc.) and obtains authorization
4. The OP responds with an ID token and/or access token
5. The RP validates the tokens and grants or denies the user access to the requested resource

Here's a simple analogy: Imagine OIDC is like using a student ID to access the university library. The librarian (RP) asks for your ID. You provide your card (access token) issued by the university admin (OP). The librarian checks the ID is current and that you have borrowing privileges (scopes). If everything checks out, the books are all yours.

OIDC protocol supports different flows for different use cases, like using refresh tokens for ongoing access or incorporating PKCE (proof key for code exchange) for added mobile security. But the core goal is always to provide secure, standards-based authentication.

What is SAML?

Security Assertion Markup Language, or SAML, is an open standard for exchanging authentication and authorization information between parties, specifically between an identity provider and a service provider (SP). It relies on XML-based assertions to pass user credentials and access rights.

The key components of SAML are:

• User - The person trying to access a service or app
• Identity provider - The system that performs user authentication and passes identity info to SPs
• Service provider - The system or app a user wants to access
• Assertion - An XML document the IdP sends to the SP containing authentication and authorization information about the user
• SAML request - An authentication request from the SP to the IdP
• SAML response - The IdP's response to the SP, containing the assertion

SAML is commonly used for web browser SSO. It allows users to authenticate with one system (the IdP) and then access other services (SPs) without having to log in again. The IdP acts as the central trusted source of identity information.

How does SAML work?

A typical SAML authentication flow goes like this:

1. A user tries to access a protected resource (SP)
2. The SP sends a SAML request to the IdP asking for authentication
3. The IdP authenticates the user (via login form, MFA, etc.)
4. The IdP sends a SAML response back to the SP with a SAML assertion
5. The SP validates the assertion and creates a local session for the authenticated user

You can think of SAML like getting into a hotel resort. You first go to the check-in desk (IdP) and show your ID to prove who you are. They give you a room key card (assertion) and direct you to your building (SP). The door scanner checks your key card is valid, then lets you in. You can then use that same key card to access other hotel amenities without having to go back to the check-in desk.SAML provides a secure, standardized way for IdPs to share authenticated identity and access information with SPs. The assertion serves as a trust mechanism between the two parties.

7 differences between SAML and OIDC

While SAML and OIDC have some similarities, there are key differences in how they work and what they're best suited for. Some of the main distinctions include:

That's not to say OIDC is "better" than SAML across the board. SAML is still the go-to for many web SSO use cases. The key is understanding the tradeoffs and aligning your choice to your specific needs.

3 similarities between SAML and OIDC

For all their differences, OIDC and SAML do share some important things in common:

1. Federated identity 

Both protocols enable federated identity—the practice of outsourcing authentication to a trusted central provider. This allows users to access multiple systems with a single set of credentials.

2. SSO

OIDC and SAML both enable web single sign-on, where users log in once to access multiple apps. They handle SSO in different ways, but the end goal of frictionless UX is the same.

3. Customization

Both standards leave room for implementers to define their own authentication policies, authorization rules, and token parameters. You can tune them to your org's specific security and compliance needs.

OIDC vs. SAML: When should you implement each?

The choice between OIDC and SAML depends on your specific use case and constraints. This section explores specific scenarios:

OIDC use cases

OIDC is quickly becoming the protocol of choice for many modern web and mobile authentication flows. Some of the most common use cases include:

• Authenticating users into client-side or native apps
• Securing microservices and APIs with granular, token-based access control
• Providing federated login for customer-facing apps and services
• Enabling SSO for a suite of internal or third-party tools

OIDC really shines in scenarios that require lightweight, mobile-friendly identity and flexible token-based authorization. By putting identity claims directly into JWTs, OIDC allows resource servers to make fast, local access decisions without additional network calls.

SAML use cases

SAML has been around longer than OIDC and is still widely used for web SSO, especially in enterprise contexts. Common scenarios include:

• Enabling employees to access multiple internal web apps with a single set of credentials
• Providing portal or partner login across company boundaries
• Supporting SSO for cloud and SaaS apps that don't have built-in user management
• Integrating with legacy systems that don't support newer protocols

SAML is a good fit when you need to enable web SSO across a variety of enterprise and custom apps. Its XML-based assertions can carry a lot of detail and are widely supported by enterprise IdPs and SPs.

Hybrid approaches 

In many cases, organizations use both SAML and OIDC, depending on the context. Legacy systems may continue to rely on SAML, while modern applications, particularly mobile apps or APIs, may prefer OIDC. Hybrid solutions can be built to ensure interoperability across both standards. ​​Common hybrid scenarios include:

• Enterprise environments with SAML for legacy systems and OIDC for new cloud/mobile apps
• B2B integrations supporting both SAML and OIDC partners
• Gradual migrations from SAML to OIDC

OIDC vs. SAML: How to choose the best protocol

So which protocol is right for you? Like we pointed earlier, the answer depends. Here are some key factors to consider:

1. Use case

What kind of resources are you looking to protect—web apps, native mobile apps, APIs? Are you focused more on employee-facing or customer-facing scenarios? Do you need to integrate with legacy on-prem systems? Consider OIDC for modern web and mobile apps, while SAML might be better for enterprise web SSO.

2. User experience

How important is seamless SSO to your users? Are you focusing on mobile-first experiences? OIDC's lightweight tokens can enable faster processing on mobile devices, while SAML works well for traditional web applications.

3. Interoperability

What kinds of systems will your authentication flow need to work with? OIDC integrates well with modern REST APIs and OAuth 2.0 systems, while SAML has strong support in enterprise environments and established identity providers.

4. Existing infrastructure

What standards do your current IdPs and apps already support? Are you looking to extend SSO to new cloud and mobile resources, or just web properties? Leveraging existing protocol support can simplify implementation and reduce development time.

5. Security and compliance

What kinds of information will you be passing in tokens and assertions? What industry regulations and standards do you need to comply with? Both OIDC and SAML provide robust security features and support encrypted data transmission.

There's rarely a one-size-fits-all answer. The key is understanding your current needs and anticipating future ones. A good identity solution should give you the flexibility to use either protocol (or both) as your needs evolve.

Rippling: Streamlined user authentication for your business 

Implementing secure authentication flows from scratch is complex. Between defining token schemas, configuring IdP and SP endpoints, and orchestrating user flows, there's a lot of plumbing to manage. That's where a solution like Rippling comes in.

Rippling is an all-in-one platform for identity and access management that makes implementing OIDC and SAML a snap. As an identity provider, Rippling uses SAML to securely pass authentication and authorization information to service providers like Google Workspace, Slack, and Asana. Users only need to log in once to Rippling, which then handles authentication with each application they try to access.

With Rippling, you can:

• Seamlessly integrate with popular IdPs like Azure AD, Okta, and Google
• Set up fine-grained access policies based on user attributes like department, title, and location
• Add MFA to any app to enhance security with additional verification steps
• Automatically provision and deprovision users as they join, move, or leave your org
• Get a centralized view of user activity across all your apps

What makes Rippling unique is that it combines an HRIS and IdP into one platform. This means user identities are unified across HR, devices, and third-party apps, ensuring data is always accurate and up to date. Rippling supports various protocols including LDAP, Active Directory (AD), OIDC, and RADIUS, as well as custom SCIM and SAML apps.

The platform includes robust security features, including role-based access controls, dynamic MFA enforcement, and detailed activity audit logs. It's also SOC 2 Type II, ISO 27001, and CSA STAR Level 2 certified, ensuring enterprise-grade security for your authentication needs.

OIDC vs. SAML FAQs

Which protocol is better for compliance with data security regulations?

Both SAML and OIDC provide strong security features suitable for regulatory compliance. SAML's maturity and extensive security controls make it popular in highly regulated industries like healthcare and finance. OIDC's modern architecture also supports robust security and compliance requirements. The choice should depend more on your specific use case than compliance alone, as both can be implemented securely.

What tools and platforms support OIDC and SAML?

Major identity providers like Google, Microsoft Azure AD, and Okta support both protocols. Most enterprise applications support SAML while modern web/mobile applications and APIs typically favor OpenID Connect. Identity management platforms like Rippling can integrate with these protocols to provide unified access control.

What industries commonly use OIDC or SAML, and why?

Large enterprises, healthcare organizations, and government institutions often use SAML due to its established presence in enterprise systems. Technology companies and digital services typically choose OIDC for its mobile-friendly design and simpler implementation. Many organizations implement both protocols to serve different needs.

How does user experience differ between OIDC and SAML?

From a user perspective, both protocols provide similar single sign-on experiences. OIDC generally offers faster authentication, particularly on mobile devices, while SAML may involve slightly longer processing times. For standard web applications, the difference in user experience is minimal.

This blog is based on information available to Rippling as of December 16, 2024.

Disclaimer: Rippling and its affiliates do not provide tax, accounting, or legal advice. This material has been prepared for informational purposes only, and is not intended to provide or be relied on for tax, accounting, or legal advice. You should consult your own tax, accounting, and legal advisors before engaging in any related activities or transactions.