Pros of Authelia

• More comprehensive authentication features, including 2FA and TOTP support
• Self-hosted solution with greater control over user data and privacy
• Active development with frequent updates and community support

Cons of Authelia

• More complex setup and configuration compared to SSO
• Requires additional infrastructure and maintenance
• May have a steeper learning curve for administrators

Code Comparison

Authelia configuration (YAML):

jwt_secret: a_very_important_secret
default_redirection_url: https://public.example.com
server:
  host: 0.0.0.0
  port: 9091

SSO configuration (YAML):

upstream_configs:
  - service: example
    default:
      from: example.com
      to: http://example.com

Both projects use YAML for configuration, but Authelia's configuration is more detailed due to its broader feature set. SSO focuses primarily on single sign-on functionality, while Authelia offers a wider range of authentication options and settings.

Authelia provides a more comprehensive authentication solution with advanced features, but requires more setup and maintenance. SSO offers a simpler, more focused approach to single sign-on, which may be preferable for organizations with straightforward authentication needs or limited resources for implementation and management.

Pros of oauth2-proxy

• Supports a wider range of OAuth providers out-of-the-box
• Simpler setup and configuration process
• More active community and frequent updates

Cons of oauth2-proxy

• Less granular access control compared to SSO
• Limited multi-factor authentication options
• Fewer enterprise-specific features

Code Comparison

SSO configuration example:

upstreams:
  - id: example
    path: /example
    uri: http://example.com
    allowed_groups:
      - example-group

oauth2-proxy configuration example:

http_address="0.0.0.0:4180"
upstreams="http://example.com"
email_domains=["example.com"]
cookie_secret="cookie_secret"
client_id="client_id"
client_secret="client_secret"

Both projects serve as reverse proxies for authenticating users via OAuth/OpenID Connect. SSO offers more advanced features for enterprise environments, including granular access control and multi-factor authentication. oauth2-proxy provides a simpler setup and supports a broader range of OAuth providers, making it more suitable for smaller projects or those requiring quick implementation. SSO's configuration focuses on defining upstreams with specific access controls, while oauth2-proxy's configuration is more straightforward, emphasizing basic OAuth settings and upstream definitions.

Pros of Vouch Proxy

• More flexible authentication options, supporting multiple providers
• Easier to set up and configure for simpler use cases
• Active development and community support

Cons of Vouch Proxy

• Less comprehensive feature set compared to SSO
• May require additional configuration for complex scenarios
• Smaller ecosystem and fewer integrations

Code Comparison

SSO (Go):

func (p *Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
    switch r.URL.Path {
    case "/ping":
        p.servePing(w, r)
    case "/sign_in":
        p.serveSignIn(w, r)
    case "/sign_out":
        p.serveSignOut(w, r)
    default:
        p.serveProxy(w, r)
    }
}

Vouch Proxy (Go):

func (v *Vouch) ValidateRequestHandler(w http.ResponseWriter, r *http.Request) {
    if r.Method != http.MethodGet {
        http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
        return
    }

    // ... (validation logic)
}

Both projects are written in Go and provide similar core functionality for authentication and authorization. SSO offers a more comprehensive proxy solution, while Vouch Proxy focuses on flexible authentication with various providers. The code snippets show different approaches to handling HTTP requests, with SSO using a switch statement for routing and Vouch Proxy implementing specific handler functions.

Pros of Pomerium

• More comprehensive identity-aware access proxy with additional features like authorization policies and service discovery
• Active development with frequent updates and a growing community
• Supports multiple identity providers and protocols out-of-the-box

Cons of Pomerium

• More complex setup and configuration compared to SSO
• Steeper learning curve for administrators and users
• May be overkill for simpler use cases where SSO's lightweight approach is sufficient

Code Comparison

SSO configuration example:

proxy_root_domains:
  - example.com
upstreams:
  - name: example
    domain: http://example.com
    static_upstreams:
      - example.com:8080

Pomerium configuration example:

authenticate_service_url: https://authenticate.example.com
authorize_service_url: https://authorize.example.com
routes:
  - from: https://example.com
    to: http://internal-app.example.com
    policy:
      - allow:
          or:
            - email:
                is: user@example.com

Both projects aim to provide secure access to internal applications, but Pomerium offers more advanced features and flexibility at the cost of increased complexity. SSO is simpler to set up and use, making it suitable for straightforward use cases, while Pomerium is better suited for organizations with more complex access control requirements.

Pros of Keycloak

• More comprehensive identity and access management solution with built-in user management, role-based access control, and multi-factor authentication
• Supports a wider range of protocols and standards, including OpenID Connect, SAML, and OAuth 2.0
• Offers a user-friendly admin console for easier configuration and management

Cons of Keycloak

• More complex setup and configuration process compared to SSO's simpler approach
• Requires more resources to run and maintain due to its extensive feature set
• May be overkill for organizations with simpler authentication needs

Code Comparison

SSO (Go):

func (p *Proxy) authenticate(w http.ResponseWriter, r *http.Request) (*sessions.SessionState, error) {
    session, err := p.sessionStore.Load(r)
    if err != nil {
        return nil, err
    }
    return session, nil
}

Keycloak (Java):

@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    AuthenticationCallback callback = new AuthenticationCallback(req, resp, deployment);
    OIDCFilterSessionStore tokenStore = new OIDCFilterSessionStore(req, resp, deployment);
    tokenStore.checkCurrentToken();
}

Both repositories provide authentication solutions, but Keycloak offers a more feature-rich platform with broader protocol support, while SSO focuses on a simpler, lightweight approach to single sign-on.