How do I implement SSO for a new application?

To implement SSO for a new application, the usual approach is to integrate your app with an Identity Provider (IdP) using a standard protocol:

• SAML 2.0 — common in enterprise environments
• OpenID Connect (OIDC) / OAuth 2.0 — modern, widely used for web/mobile/apps
• LDAP/AD — sometimes used internally, but usually not true SSO by itself

Typical implementation steps

1) Pick the SSO protocol

Choose based on your environment:

• OIDC: best default for new apps
• SAML: common if your customers use enterprise SSO providers
• Both if you need broad compatibility

2) Choose the Identity Provider

Examples:

• Okta
• Azure AD / Entra ID
• Auth0
• Google Workspace
• Ping Identity
• Keycloak

3) Register your application with the IdP

You’ll configure:

• App name
• Redirect/callback URLs
• Logout URLs
• Allowed scopes/claims
• Signing certificates/keys
• Client ID and client secret (for OIDC)

4) Implement the login flow

For OIDC, the common flow is:

1. User clicks “Sign in”
2. Your app redirects them to the IdP
3. User authenticates at the IdP
4. IdP redirects back to your app with an authorization code
5. Your backend exchanges the code for tokens
6. Your app creates a local session

For SAML:

1. User is redirected to IdP
2. IdP sends a signed SAML assertion to your ACS endpoint
3. Your app validates the assertion
4. Your app creates a local session

5) Validate identity securely

Make sure you validate:

• Token/signature authenticity
• Issuer
• Audience/client ID
• Expiration
• Nonce/state values
• Redirect URI exact match
• SAML certificate and assertion conditions

6) Map user identities to your app

Decide how to handle:

• New users vs existing users
• Email as unique identifier
• Roles/groups/permissions
• Just-in-time provisioning vs pre-provisioned accounts

7) Add logout handling

Implement:

• Local app logout
• Optional IdP logout / single logout where supported

8) Test thoroughly

Test:

• Login success/failure
• Expired tokens/assertions
• User already signed in
• Role/group mapping
• IdP downtime
• Account linking and provisioning

---

Best practice recommendation

If you’re starting a new application, use OpenID Connect unless you specifically need SAML for enterprise integration.

---

Minimal architecture

• Frontend: redirects to IdP and handles callback
• Backend: exchanges authorization code, validates tokens, creates app session
• Database: stores app user profile and authorization mapping

---

Questions to answer before implementation

1. Is this a web app, mobile app, desktop app, or API?
2. Do your customers need SAML, OIDC, or both?
3. Which IdP(s) must you support?
4. Do you need user provisioning/deprovisioning?
5. Do you need role/group sync?
6. Do you want “login with company account” only, or social login too?

If you want, I can give you:

• a step-by-step OIDC implementation guide
• a SAML setup guide
• or sample code for a specific stack like Node.js, Python, Java, .NET, or React.