SSO allows users to authenticate once and gain access to multiple applications without needing to log in repeatedly. SSO makes login easier and provides better security by managing authentication effectively through a single login. It also enhances user experience by reducing friction in accessing user accounts and improving the way authentication service providers handle user record validation.
What this guide covers
In this guide, you’ll implement enterprise-ready SSO in a Spring Boot application using Scalekit. By the end, you’ll:
Set up a login route that generates a secure authorization URL
Handle the callback and verify the one-time authorization code
Fetch user details from the identity provider
Establish user sessions using secure cookies or Spring session management
Support enterprise IdPs like Okta, OneLogin, Entra ID, or JumpCloud
Test your flow locally with Scalekit’s IdP simulator, and go live with real credentials
Overview of how SSO fits into a Spring Boot application
Spring Boot, which uses the Spring Security framework, offers support for implementing Java SSO using OAuth 2.0 or OpenID Connect (OIDC). Here’s how.
Authentication management: Spring Security handles redirects to external Identity Providers (IdPs) for user login, social login, and SP-initiated SSO flows
Token management: Access tokens are used for resource authorization, containing user info for identity verification
Role-based Access Control (RBAC): Define and enforce user roles based on token claims and the structure of your user model
Manual SSO in Java is complex and slow
The manual setup of SSO in Java Spring Boot results in adding too many complexities to the system. Although Spring Security integrates with OAuth 2.0 and OIDC by default, it proves hard to incorporate several IdPs with SAML and other protocols. SP-initiated SSO setups require careful handling of URL patterns, user info, and configuration files.
Let’s explore how this complexity unfolds in real-world scenarios.
Example: LedgerStack’s painful auth setup
LedgerStack, a fictional financial SaaS platform built using Spring Boot, faced the daunting task of integrating with four major enterprise customers—each using a different IdP: Okta, OneLogin, Entra ID, and JumpCloud. These integrations required robust Java SSO solutions that involved managing different user record formats and service provider configurations.
Pain points: Why manual SSO was a nightmare
Fragmented authentication flows: Each IdP had its own protocol quirks, requiring custom logic for handling SAML assertions, OIDC token exchanges, and session management with varied user model structures
Bloated codebase: Developers had to manually parse SAML responses, validate signatures, and implement token refresh logic, resulting in over 1,200 lines of authentication code spread across different services. This complexity highlighted the need for a streamlined Java SSO solution as configuration files became a pain to maintain
Error-prone integrations: Minor differences in XML schema, signing algorithms, and redirect URIs led to frequent login failures and debugging nightmares. User info mismatches were common
Slow customer onboarding: Every new enterprise integration took weeks of development and testing, delaying LedgerStack’s ability to onboard clients efficiently. Multiple user records and service provider mismatches needed to be resolved
The Scalekit solution
If LedgerStack swtiched to Scalekit, it could eliminate 1,200+ lines of complex authentication code and replace it with a few simple API calls. The benefits could be immediate:
Drastically reduced codebase, freeing developers from maintaining low-level SAML/OIDC logic
Enterprise customers onboarded in hours instead of weeks, thanks to Scalekit’s prebuilt IdP connectors
Reliable authentication flows, with built-in error handling, session management, and compliance with security best practices
Simplified mapping of user info to their internal user model
Scalekit eliminates the complexity of implementing SSO in Java by providing an intuitive SDK that abstracts away the intricacies of authentication protocols like SAML and OIDC. Whether you're building with Spring Boot, Spark, or Micronaut, Scalekit handles the authentication flows without requiring you to write low-level code or parse XML manually.
We use ScaleKit for enterprise SSO, and as a small team, it has been a game-changer for us. Integrating with each SSO provider individually is complex and time-consuming, and managing IT teams across different businesses adds another layer of difficulty. ScaleKit simplifies this by providing a centralized platform where we can handle all SSO requirements efficiently. This not only saves us significant development time but also ensures a seamless authentication experience for our users across multiple organizations. — Review on G2
Key benefits of using Scalekit for SSO
Unified SDK for SAML and OIDC
With Scalekit’s Java SDK, you don’t need separate implementations for different authentication protocols. When you implement SSO in Java, it can be complex, but Scalekit simplifies the process. It supports both SAML and OpenID Connect (OIDC) out of the box, seamlessly managing token exchanges, assertion parsing, and error handling.
No protocol internals or assertion parsing
Instead of dealing with cryptic SAML assertions or JWT claims manually, Scalekit abstracts these tasks using its SDK. You simply get a clean user identity object, eliminating the need to write complex XML parsing code.
End-to-end SSO flow with Scalekit
Here’s how the full authentication flow works using Spring Boot and Scalekit:
User clicks “Login with SSO”
Your backend uses Scalekit’s SDK to generate an authorization URL
User is redirected to their assigned Identity Provider (e.g., Okta, Entra ID)
After login, the IdP redirects back to your app with an authorization code
Your app exchanges the code for user identity details via the SDK
You establish a session using a secure cookie or Spring’s session manager
Setting up an SSO authentication server with Spring Security
This section will guide you through integrating Scalekit with Spring Boot to build a secure SSO authentication server. We’ll focus on backend logic, Scalekit configuration, and session management.
Prerequisites
Ensure you have the following:
Java 17+
Spring Boot 3+
OAuth 2.0 Identity Provider (e.g., Okta, Auth0, or a custom IdP)
Spring Security dependencies
Scalekit SDK
Install the SDK
Configuring Scalekit for SSO
Before integrating Scalekit into your Spring Boot application, you need to configure it with your Identity Provider (IdP). Follow these steps:
Create a secure authorization URL to redirect users to the IdP for authentication:
AuthorizationUrlOptions options = new AuthorizationUrlOptions();
options.setConnectionId("conn_123456789"); // Use connectionId, orgId, or loginHintString
redirectUrl = "https://your-app.com/callback";
String authorizationUrl = client.authentication().getAuthorizationUrl(redirectUrl, options).toString();
Test with IdP Simulator
For testing without a real IdP, Scalekit provides an IdP Simulator.
Use a test domain like user@example.org to simulate login flows
Validate various login scenarios without setting up actual IdPs
🚪 Run with real IdPs:
Replace connection ID and credentials with production config
Redirect users to their enterprise IdP with one line of code
Managing sessions in Java apps
After the user authenticates, you’ll receive an ID token. To manage the session securely, follow these steps:
1. Create a secure cookie
Cookie sessionCookie = new Cookie("id_token", idToken);
sessionCookie.setHttpOnly(true);
sessionCookie.setSecure(true); // Enable for HTTPSresponse.addCookie(sessionCookie);
2. Use Spring’s session manager
Alternatively, use Spring Boot’s session management for enhanced control:
HttpSession session = request.getSession();
session.setAttribute("idToken", idToken);
session.setAttribute("user", user); // Store user data securely
Best practices for secure Java SSO
To ensure a secure and robust SSO implementation, follow these best practices:
Enforce HTTPS: Always use HTTPS for login and callback routes to prevent data interception
Rotate API secrets: Regularly rotate your Scalekit API keys and client secrets to minimize security risks
Enable MFA: Configure Multi-Factor Authentication (MFA) on the IdP side for additional security
Log authentication events: Capture detailed logs of all authentication attempts using Scalekit’s logging features and Spring Boot’s logging framework
Validate callback parameters: Ensure all callback parameters (code, state, etc.) are properly validated to prevent CSRF and authorization code attacks
Use meaningful default values in your configuration files and ensure consistency across environments
Review URL patterns and ensure consistency between your app and the service provider
Wrapping up
Scalekit transforms weeks of manual SAML parsing and error-prone XML management into a simple, reliable SDK integration for Java Spring SSO. With its built-in support for major IdPs, you get a unified authentication experience across all enterprise customers.
Whether you’re working with Spring Boot, Tomcat, or a custom Java HTTP server, Scalekit reduces complex Java SSO implementation authentication workflows to just a few lines of code.
Start locally: Test using Scalekit’s IdP Simulator
Connect real IdPs: Configure actual providers through the dashboard
Go live: Deploy with enterprise-grade authentication security using Java Spring SSO
FAQs
Can I use Scalekit SSO in any Java framework, or is it limited to Spring Boot?
Scalekit’s Java SDK is compatible with any Java backend, including Spring Boot, Micronaut, Spark, or even a custom HTTP server. It easily integrates into standard authentication pipelines.
How does Scalekit reduce the lines of code needed for SAML or OIDC?
Scalekit handles protocol intricacies, eliminating the need for custom XML parsers or SAML assertion management. You only need a few function calls to manage authentication and authorization requests.
How do I handle secure sessions after login in a Spring Boot app?
After successful authentication, store the idToken (a JWT containing user claims) in a HttpOnly and Secure cookie. Avoid storing tokens in localStorage. Extract claims like email and user ID from the token and manage sessions using Spring Security or a session manager.