What Is Single Sign-On (SSO) and How Does It Work?

Are your employees constantly forgetting passwords? Do multiple logins slow down productivity or create security risks for your organization?

If so, you’re not alone. Modern workplaces rely on dozens of applications, and managing separate credentials for each one can be frustrating and risky. That’s where Single Sign-On (SSO) comes in. With SSO, users log in once and gain secure access to all their apps, while IT teams get centralized control and better visibility into who’s accessing what.

In this guide, we’ll break down exactly what SSO is, how it works, and why it matters for your organization. You’ll also learn how passwordless platforms like OLOID can make SSO even more secure and seamless, helping your teams stay productive without compromising on safety.

What Is Single Sign-On (SSO)?

Single Sign-On (SSO) is an authentication method that enables users to access multiple applications and services with just one set of login credentials. Instead of remembering dozens of usernames and passwords, a user logs in once, and the system grants access to all connected apps they’re authorized to use.

At its core, SSO centralizes authentication. Instead of each application verifying a user individually, a trusted Identity Provider (IdP) handles login validation. Once verified, the user receives a secure token or assertion that tells other applications, “This person is authenticated, let them in.”

SSO is widely used in modern workplaces, especially as organizations adopt numerous SaaS applications, cloud platforms, and internal systems. Common examples include logging into Google Workspace or Microsoft 365 and automatically gaining access to associated apps without having to re-enter credentials.

Types of Single Sign-On

Single Sign-On isn’t a one-size-fits-all solution. Different organizations use different SSO solutions based on their apps, security needs, and user workflows.

1. Web-Based SSO

Web-based SSO enables authentication across browser-based applications and cloud services, eliminating the need for separate logins. Users authenticate once through their browser and gain seamless access to multiple SaaS applications.

This approach works by exchanging authentication tokens between the Identity Provider and web applications. Modern enterprises rely heavily on web-based SSO for managing access to cloud platforms.

Key Characteristics of Web-Based SSO

• Works entirely through web browsers without requiring client software installation.
• Ideal for organizations that use multiple SaaS applications, such as Salesforce, Microsoft 365, and Google Workspace.
• Supports popular authentication protocols, including SAML and OpenID Connect.
• Enables seamless navigation between different cloud services without repeated login prompts.

2. Enterprise SSO

Enterprise SSO integrates authentication across internal corporate systems, legacy applications, and modern cloud platforms, providing a unified approach to authentication. This approach extends beyond web applications to include desktop software, network resources, and on-premises systems.

Organizations use enterprise SSO to unify access across their entire technology stack. It provides comprehensive identity management for employees accessing diverse internal resources.

Key Characteristics of Enterprise SSO

• Supports both cloud-based and on-premises applications within corporate networks.
• Integrates with Active Directory, LDAP, and other enterprise directory services.
• Enables authentication for VPNs, file shares, and internal business applications.
• Often requires additional software agents or connectors for integrating legacy systems.

3. Federated SSO

Federated SSO enables secure authentication and access across different organizations and security domains. This approach allows users from one organization to access resources in partner organizations seamlessly.

Federated identity creates trust relationships between separate identity systems without merging user directories. Companies use this for supplier portals, customer access, and inter-organizational collaboration.

Key Characteristics of Federated SSO

• Establishes trust relationships between independent organizations without sharing user databases.
• Enables secure collaboration with partners, vendors, and customers across organizational boundaries.
• Commonly used in B2B scenarios, supply chain management, and consortium arrangements.
• Relies on identity federation standards to exchange authentication and authorization information.

4. Common Protocols

SSO implementations rely on standardized protocols that define how authentication information is exchanged securely. These protocols ensure compatibility between different vendors and enable interoperability across diverse systems.

Understanding these protocols helps organizations make informed decisions about SSO architecture. Each protocol offers specific advantages suited to different authentication scenarios and security requirements.

Primary SSO Protocols

• SAML (Security Assertion Markup Language): Enterprise-focused protocol for exchanging authentication and authorization data between Identity Providers and Service Providers.
• OAuth 2.0: Authorization framework that enables applications to obtain limited access to user accounts without exposing passwords.
• OpenID Connect: Authentication layer built on OAuth 2.0, providing identity verification and user profile information.
• Kerberos: A network authentication protocol commonly used in Windows environments for enterprise SSO implementations.

Understanding the different types of SSO helps you choose the right approach, but to see how it actually works in practice, let’s walk through the step-by-step authentication flow.

How Single Sign-On Works

SSO authentication follows a systematic process that verifies user identity and grants access to multiple applications. The process involves coordination between users, Identity Providers, and Service Providers. Each step ensures security while maintaining a seamless user experience across connected applications.

1. User Initiates Login

The user attempts to access an application or service through their browser or device. Instead of presenting a local login form, the application recognizes that it requires SSO authentication. The Service Provider redirects the user to the configured Identity Provider for authentication. This redirection occurs automatically and transparently, creating a seamless user experience.

2. Identity Provider Authenticates User

The Identity and Access Provider prompts the user to enter their credentials if not already authenticated. Authentication methods include traditional username and password, multi-factor authentication, or biometric verification.

The IdP validates credentials against its user directory or authentication database. Once verified, the IdP determines what permissions and attributes apply to this user.

3. Authentication Token is Issued

The Identity Provider generates a secure authentication token or assertion after successful verification. This token contains encrypted information about the user's identity, permissions, and authentication status.

Token formats vary based on the protocol used, including SAML assertions or JWT tokens. The token includes timestamps and digital signatures to prevent tampering and replay attacks.

4. Token is Sent to the Application

The IdP redirects the user's browser back to the requesting application with the authentication token. The Service Provider receives the token and validates its authenticity and integrity.

Validation includes verifying digital signatures, expiration dates, and the trustworthiness of the issuing Identity Provider. This verification ensures tokens haven't been tampered with or stolen during transmission.

5. User Gains Access

After successful token validation, the Service Provider grants the user access to the requested application. The user can now use the application without entering any additional credentials.

When accessing other SSO-enabled applications, the same token provides authentication without repeated logins. This seamless experience continues until the session expires or the user logs out.

Now that you understand how SSO streamlines authentication, let’s explore the key benefits it brings to both users and organizations.

[[cta]]

Key Advantages of Implementing Single Sign-On

Implementing Single Sign-On offers more than just convenience. It strengthens security, boosts productivity, and simplifies access management for your entire organization. These advantages become increasingly valuable as companies scale and adopt more applications.

1. Improves Security

SSO reduces password fatigue by requiring users to remember only one strong credential. When people manage fewer passwords, they're more likely to create and maintain strong ones.

Centralized authentication enables consistent enforcement of password policies and security requirements across all applications. Organizations gain better visibility and control over who accesses what resources throughout the enterprise.

2. Enhances User Experience

SSO eliminates the frustration of managing multiple passwords and repeated login prompts. Employees can move seamlessly between applications without interrupting their workflow for authentication.

This improved experience reduces friction and helps workers stay focused on productive tasks. Users spend less time on password-related issues and more time on value-adding activities.

3. Increases Productivity

IT help desk teams spend a significant amount of time resetting forgotten passwords and resolving access issues. SSO dramatically reduces password reset requests, freeing IT staff for more strategic work.

New employees can be onboarded quickly with immediate access to the necessary applications. When employees leave, access can be revoked centrally rather than in each system.

4. Improves Compliance and Risk Management

Many regulatory frameworks require organizations to demonstrate strong access controls and audit capabilities. SSO provides centralized logging of authentication events and access patterns for compliance reporting.

Organizations can quickly respond to audit requests with comprehensive access reports from a single source. Centralized control enables consistent enforcement of security policies across all systems.

These benefits highlight the importance of implementing SSO in your organization’s authentication strategy. With these advantages in mind, let’s look at some common ways organizations put SSO to work across different teams and applications.

[[cta-2]]

Common Single Sign-On Use Cases

From employees logging into multiple apps to partners accessing shared platforms, SSO makes day-to-day access simpler, faster, and more secure. Understanding common use cases helps identify opportunities for SSO implementation in your organization. Primary SSO use cases include:

• Employee access to corporate apps: Workers authenticate once in the morning and gain seamless access to email, CRM, project management tools, HR systems, and other business applications throughout the day without repeated logins.
• Partner or vendor collaboration portals: External partners and suppliers can access shared resources, supply chain systems, and collaboration platforms using their own organizational credentials through federated SSO arrangements.
• Educational institutions managing student and faculty logins: Universities and schools provide students and staff single-credential access to learning management systems, library resources, email, registration systems, and campus applications.
• Customer portals for SaaS products: Software companies enable customers to access support portals, billing systems, product documentation, and community forums using a single set of credentials, thereby improving the overall customer experience.
• Healthcare patient data access: SSO for healthcare enables doctors, nurses, and administrative staff to access electronic health records, lab systems, imaging platforms, and billing applications while maintaining HIPAA compliance and audit trails.
• Manufacturing and production systems: Manufacturing facilities provide workers secure access to production planning software, quality management systems, inventory tracking, and equipment monitoring dashboards using SSO for operational efficiency and data security.

These use cases demonstrate just how SSO can streamline workflows, enhance security, and improve the overall user experience across employees, partners, and customers. Understanding these applications sets the stage for the next step: exploring the practical implementation process so your organization can start reaping these advantages efficiently and securely.

Step-By-Step SSO Implementation Process

Successfully implementing SSO requires careful planning, systematic execution, and ongoing management to ensure security and usability. Organizations should follow a structured approach to minimize disruption while maximizing benefits. 

Step 1: Assess Your Organization’s Needs

Start by identifying which applications require SSO integration and which users will benefit most. Document current authentication challenges, security requirements, and compliance obligations that SSO should address.

Assessment Considerations

• Catalog all applications currently in use and their authentication methods.
• Identify high-priority systems based on usage frequency and security sensitivity.
• Evaluate current pain points, such as password reset volumes and security incidents, to identify areas for improvement.
• Define success criteria and key performance indicators for the SSO implementation.

Step 2: Choose an Identity Provider (IdP)

Select an Identity Provider that supports your required protocols, integrates seamlessly with your existing systems, and scales to accommodate your organization's growth. Evaluate SSO solutions based on features, reliability, support quality, and total cost of ownership.

Some of the most popular SSO vendors include Okta, Microsoft Entra ID, and Oracle SSO. For frontline industries like manufacturing, retail, and healthcare, OLOID’s SSO-enabled passwordless authentication platform offers the perfect balance of speed, convenience, and security.

Selection Criteria

• Support for required protocols like SAML, OAuth 2.0, and OpenID Connect.
• Integration capabilities with your directory services and existing identity management systems.
• Vendor reputation, service level agreements, and customer support quality.
• Pricing models include per-user costs, implementation fees, and ongoing maintenance expenses.

Step 3: Plan the Integration

Develop a detailed integration plan that sequences application connections based on priority and complexity, ensuring a logical and efficient workflow. Identify technical requirements, potential challenges, and resource needs for each integration. Create a timeline with realistic milestones and contingency plans in place to address possible issues.

Planning Elements

• Prioritize applications for SSO integration, starting with high-impact, low-complexity systems.
• Map authentication flows and identify required attributes for each application.
• Assign responsibilities to technical team members for different integration tasks.
• Establish testing environments to validate integrations before deploying them in production.

Step 4: Configure the Identity Provider

Set up your chosen Identity Provider with appropriate user directories, authentication policies, and security settings. Configure password requirements, multi-factor authentication options, and session management policies that align with security requirements.

Configuration Tasks

• Import or synchronize user data from existing directories like Active Directory or LDAP
• Define authentication policies, including password complexity, MFA requirements, and session timeouts.
• Configure user attributes and claims that applications need for authorization decisions.
• Set up security features, such as conditional access policies and risk-based authentication, to enhance security.

Step 5: Integrate Applications with SSO

Connect individual applications to the Identity Provider following each vendor's specific integration requirements. Configure applications to redirect authentication requests to the IdP and accept its tokens. Test each integration thoroughly to ensure users can authenticate and access resources properly.

Integration Steps

• Register each application with the Identity Provider as a Service Provider.
• Configure application settings to redirect authentication to the IdP endpoint.
• Map user attributes from IdP assertions to application-specific attributes.
• Implement logout functionality to properly terminate sessions across all applications.

Step 6: Test and Validate

Conduct comprehensive testing with pilot user groups before deploying the organization-wide to identify and resolve issues. Test all authentication scenarios, including initial login, accessing multiple applications, logout, and error conditions.

Testing Activities

• Perform functional testing of login flows, attribute mapping, and authorization rules.
• Conduct security testing to verify token handling, session management, and access controls.
• Test edge cases, such as password resets, account lockouts, and concurrent sessions, to ensure optimal performance.
• Gather feedback from pilot users regarding their experience, performance, and any issues they encounter.

Ste 7: Rollout and Train Users

Deploy SSO gradually to minimize disruption, starting with pilot groups before expanding organization-wide. Provide clear communication, training materials, and support resources to help users transition smoothly and effectively.

Rollout Considerations

• Create user documentation that explains the new login process and outlines the expected changes.
• Conduct training sessions or provide video tutorials demonstrating SSO usage.
• Establish dedicated support channels for SSO-related questions during the transition period.
• Monitor help desk tickets and user feedback to identify and address common issues.

Step 8: Monitor and Maintain

Continuously monitor SSO performance, security events, and user feedback to ensure optimal operation and ensure optimal performance. Regularly review access logs, update policies, and add new applications as organizational needs evolve.

Ongoing Activities

• Monitor authentication success rates, response times, and error patterns to identify areas for improvement.
• Review security logs for suspicious activity, such as failed login attempts or unusual access patterns.
• Update user attributes and permissions as organizational roles change.
• Integrate new applications as the organization adopts them.

Once your SSO is set up and running smoothly, the next step is selecting the right solution that fits your organization’s specific needs, integrations, and security requirements.

How to Choose the Right SSO Solution?

Selecting the appropriate SSO provider requires careful evaluation of technical capabilities, business requirements, and long-term strategic fit. The right Single Sign-On solution balances security, usability, integration capabilities, and cost effectiveness for your specific environment.

Here are the key factors to consider while evaluating SSO solution providers: 

• Integration capabilities: Verify the solution supports your existing applications, authentication protocols, and directory services with pre-built connectors or flexible APIs for custom integrations.
• Scalability and performance: Ensure the platform can handle your current user base and future growth without degrading performance during peak usage periods.
• Security features: Look for advanced capabilities like adaptive authentication, risk-based access control, detailed audit logging, and compliance with relevant security standards.
• Deployment options: Consider whether a cloud-based, on-premises, or hybrid deployment model best fits your infrastructure, security policies, and operational capabilities.
• Vendor support and reputation: Evaluate the provider's track record, customer references, support responsiveness, and long-term viability in the market.

Total cost of ownership: Calculate licensing fees, implementation costs, ongoing maintenance expenses, and internal resource requirements to understand actual costs.

[[cta-3]]

Improve Security and Streamline Authentication With Passwordless SSO From OLOID

Single Sign-On has transformed how modern organizations manage access by reducing login friction, improving user productivity, and giving IT teams centralized visibility and control. But as threats evolve and environments grow more distributed, businesses need more than simplified authentication. They need a future-ready, passwordless approach that aligns with zero-trust principles.

OLOID’s frontline passwordless authentication platform takes SSO a step further by eliminating passwords entirely and unifying physical and digital identity into one secure, seamless experience. Employees can access critical systems and physical entry points using secure, biometric-powered, consent-based authentication. This not only strengthens security but also ensures faster, smoother access across every part of the workplace.

As organizations move toward modern, integrated authentication, OLOID offers the platform to make that transition effortless. Ready to see it in action? Book a demo and discover how OLOID can transform your workforce authentication.

Frequently Asked Questions on Single Sign-On

1. Which applications can be integrated with SSO?

Most modern cloud applications and SaaS platforms support SSO integration through standard protocols like SAML and OpenID Connect. Popular business applications, including Microsoft 365, Google Workspace, Salesforce, and Slack, as well as thousands of other services, offer pre-built SSO connectors.

Integration options include:

• Cloud-based SaaS applications with native SAML or OAuth support.
• On-premises enterprise applications through connectors or gateways.
• Custom-built applications using standard authentication libraries.
• Legacy systems via proxy services or specialized integration tools.

2. What are the most common SSO protocols?

SAML, OAuth 2.0, and OpenID Connect represent the three dominant protocols for SSO implementations today. Each protocol serves specific use cases and offers different advantages for authentication and authorization scenarios.

Protocol overview:

• SAML 2.0: Mature enterprise standard for exchanging authentication data between Identity Providers and applications.
• OAuth 2.0: Authorization framework that grants applications limited access to user resources without sharing passwords.
• OpenID Connect: Modern authentication layer built on OAuth 2.0, providing identity verification capabilities.
• Kerberos: A Network authentication protocol commonly used in Windows Active Directory environments.

3. Is single sign-on completely secure?

SSO significantly improves security compared to traditional password management, but requires proper implementation and supporting controls. SSO reduces password-related vulnerabilities, such as weak credentials, password reuse, and phishing attacks.

However, organizations must implement multi-factor authentication, secure session management, and robust Identity Provider security to leverage the benefits of SSO fully. The centralized nature of SSO means securing the Identity Provider becomes critically essential for overall protection.

4. Can SSO be used across multiple organizations or partners?

Yes, federated SSO enables secure authentication across organizational boundaries without sharing user databases or credentials. Organizations establish trust relationships that allow users from one domain to access resources in partner domains seamlessly.

This capability supports B2B collaboration, supply chain integration, and customer access scenarios. Federated SSO uses standards like SAML and OAuth to exchange identity information securely between independent organizations.

5. How does SSO improve compliance and audit readiness?

SSO centralizes authentication logging, making it easier to track who accessed what resources and when. Organizations can generate comprehensive audit reports from a single source rather than collecting logs from individual applications. This centralized visibility helps demonstrate compliance with regulations requiring access controls and audit trails.

Compliance benefits:

• Provides detailed audit trails showing all authentication and access events.
• Enables consistent enforcement of access policies across all connected applications.
• Simplifies compliance reporting for regulations like GDPR, HIPAA, and SOX.
• Supports rapid access revocation when employees leave or roles change.

6. What should I look for when choosing an SSO provider?

When evaluating SSO solutions, focus on integration capabilities, security features, scalability, and vendor support. The ideal provider should support your existing applications and future needs while delivering reliable performance.

Key selection criteria:

• Pre-built connectors for your critical applications, along with flexibility for custom integrations.
• Advanced security features, including MFA, adaptive authentication, and threat detection.
• Scalability to support your user base and performance requirements.
• Strong vendor reputation, customer support, and long-term product roadmap.
• Transparent pricing and total cost of ownership are aligned with your budget.

7. How much does implementing SSO cost?

Implementing SSO can range from free for basic setups to thousands of dollars annually. Free, open-source options exist, while paid solutions typically cost between $2 and over $12 per user per month. Total costs depend on user volume, required features, integration complexity, and vendor pricing models.

Factors influencing the cost:

• User volume: Most services price per user per month, so larger organizations pay proportionally more.
• Feature requirements: Basic SSO starts at approximately $2 per user per month, while advanced features, such as MFA and adaptive security, increase costs to $6-12 or more per user per month.
• Vendor pricing models: Tiered plans offer different feature sets, and some vendors charge separately for SSO, MFA, and identity management features.
• SSO tax: Some SaaS vendors require expensive tier upgrades just to access SSO functionality.
• Integration and support: Complex setups requiring third-party assistance increase implementation costs, while ongoing training and maintenance add recurring expenses.

8. Can SSO work with mobile and legacy applications?

Modern SSO solutions support mobile applications through mobile SDKs and standard protocols, such as OAuth and OpenID Connect. Mobile apps can leverage device-native authentication capabilities, including biometric, while maintaining SSO benefits. Legacy applications present more challenges but can often be integrated using gateway services, proxy authentication, or screen-scraping tools. Organizations may need to invest in modernization or utilize specialized integration tools for applications that lack native SSO support.