OAuth & SSO Examples - Inspiration & Best Practices

OAuth 2.0 and Single Sign-On (SSO) form the foundation of modern authentication. OAuth enables users to grant applications limited access to their data at another service without sharing their password. SSO makes it possible to log in to multiple applications with a single set of credentials. Together they improve both user experience and security. Below we show how organisations implement OAuth and SSO in practice.

Enterprise SSO with SAML and OIDC

A B2B SaaS platform implemented enterprise SSO supporting both SAML 2.0 and OpenID Connect. Large customers connect their corporate identity provider (Azure AD, Okta, Google Workspace) so employees log in with their company account without a separate password. The platform detects the email address domain and automatically redirects to the appropriate identity provider. Just-in-time provisioning automatically creates a user account on first login.

• Dual-protocol support for SAML 2.0 and OpenID Connect
• Domain-based automatic redirect to corporate IdP
• Just-in-time user provisioning on first SSO login
• SCIM protocol for automated user lifecycle management

Social login with multiple providers

A consumer app offers social login via Google, Apple, GitHub, and Microsoft. The OAuth 2.0 Authorization Code flow with PKCE protects against code interception attacks. On first login, the social account is linked to an internal profile. Account linking allows users to connect multiple social providers to one account, so they can log in through any connected platform.

• OAuth 2.0 Authorization Code flow with PKCE for all providers
• Account linking for multiple social providers per account
• Automatic profile population with data from social provider
• Fallback to email/password login for users without a social account

Microservices authentication with token exchange

A microservices platform implemented OAuth 2.0 Token Exchange (RFC 8693) for service-to-service authentication. The API gateway validates the user token and exchanges it for a service-specific token with limited scope. Each microservice receives only the claims relevant to its function. Token introspection at a central authorization server prevents the use of revoked tokens.

• OAuth 2.0 Token Exchange for service-to-service authentication
• Scope-limited tokens per microservice following least-privilege
• Token introspection for real-time validation of token validity
• Short token lifetime with refresh token rotation

Multi-tenant platform with tenant-specific IdPs

A multi-tenant platform lets each tenant configure their own identity provider. Tenant A uses Azure AD, Tenant B uses Okta, and Tenant C uses Google Workspace. A tenant resolver determines which IdP configuration to use based on the subdomain or email domain. The default login page adapts dynamically: enterprise tenants see a "Login with SSO" button, while smaller tenants retain the standard email/password flow.

• Tenant-specific IdP configuration via admin panel
• Dynamic tenant resolution based on subdomain or email domain
• Adaptive login page: SSO button or standard login per tenant
• IdP metadata caching for fast authentication redirects

API platform with OAuth 2.0 machine-to-machine flow

An API platform implemented the OAuth 2.0 Client Credentials flow for machine-to-machine integrations. External systems register an OAuth client, receive a client_id and client_secret, and request access tokens from the token endpoint. Tokens contain scopes that determine which API endpoints are accessible. Automatic token rotation and tracking of token usage per client provide security and monitoring.

• Client Credentials flow for server-to-server authentication
• Scope-based authorisation per registered OAuth client
• Automatic client secret rotation with grace period
• Token usage monitoring and anomaly detection per client

Key takeaways

• Support both SAML 2.0 and OIDC to offer the broadest compatibility with enterprise identity providers.
• PKCE is essential in all public OAuth flows to prevent code interception attacks.
• Just-in-time provisioning and SCIM automate user lifecycle management in SSO integrations.
• Token Exchange and scope limitation implement least-privilege authentication in microservices.
• Tenant-specific IdP configuration is a must-have for serious multi-tenant B2B platforms.

How MG Software can help

MG Software implements secure OAuth and SSO solutions that make your authentication seamless and enterprise-ready. From social login and SAML integration to token exchange in microservices and multi-tenant IdP configuration — we ensure your users log in securely and effortlessly, regardless of the complexity of your authentication landscape.