Best Self Hosted Alternatives to Duo Single Sign-On

Keycloak is an open-source Identity and Access Management (IAM) server for modern applications and services. It centralizes authentication and authorization so applications can rely on standards-based SSO instead of implementing login, user storage, and session management.

Key Features

• Single sign-on and single sign-out across multiple applications
• Support for standard protocols: OpenID Connect, OAuth 2.0, and SAML 2.0
• Identity brokering and social login via configurable identity providers
• User federation with LDAP and Active Directory, with extensible provider support
• Admin console for managing realms, clients, users, roles, sessions, and policies
• Account management console for end users (profile, password changes, session management, and 2FA)
• Fine-grained authorization services for policy-based access control

Use Cases

• Centralized SSO for internal apps, APIs, and microservices
• Replacing custom authentication with standards-based identity and token issuance
• Integrating enterprise directories (LDAP/AD) and external identity providers into one login flow

Limitations and Considerations

• Operating securely at scale requires careful configuration of realms, clients, token lifetimes, and session settings
• Some advanced deployments may require external databases and clustering planning for high availability

Keycloak is widely used as a central identity provider to standardize authentication and access control across heterogeneous systems. It reduces application complexity while enabling consistent security policies and user management in one place.

Authelia is an open-source authentication and authorization server that provides identity and access management (IAM) for web applications. It commonly sits behind a reverse proxy to enforce single sign-on (SSO), multi-factor authentication (MFA), and fine-grained access policies.

Key Features

• OpenID Connect 1.0 provider (OpenID Certified) with OAuth 2.0 support for SSO integrations
• Reverse-proxy companion mode to allow, deny, or redirect requests based on authentication state
• Multiple MFA methods including TOTP and WebAuthn/FIDO2 security keys
• Granular authorization policies based on users, groups, domains, and resources
• Brute-force protection and login regulation/lockout controls
• Password reset flows (including LDAP or internal users) with email validation
• High availability-oriented design suitable for running multiple instances

Use Cases

• Protect internal tools and self-hosted apps behind a reverse proxy with SSO and MFA
• Provide an OIDC identity layer for applications that support OAuth2/OIDC login
• Enforce access control policies for different user groups across multiple domains

Authelia is a lightweight, security-focused IAM component that can centralize authentication and authorization for many web applications. It is particularly well-suited for homelabs and organizations that want modern SSO and MFA without adopting a full enterprise directory suite.

authentik is an open-source Identity Provider designed for modern single sign-on and authentication workflows. It provides protocol support and configurable authentication flows to secure web, API, and remote-access use cases.

Key Features

• Supports standard identity protocols: OAuth2 / OIDC, SAML2, LDAP, RADIUS, SCIM and Kerberos for broad application compatibility
• Flexible multi-stage authentication flows, policy engine, and enrollment flows for MFA and conditional access (GeoIP, impossible-travel checks)
• MFA and modern second-factor support including TOTP and WebAuthn (passkeys)
• Application proxy / outpost model for protecting internal apps and enabling remote access (RDP, SSH, VNC) behind the IdP
• Rich admin, user, and flow interfaces plus REST APIs and SDKs for automation and integration
• Pluggable federation and social login sources, fine-grained policies, and templates for customizing login and enrollment behavior
• Deployment options and tooling for Docker Compose, Kubernetes (Helm), and cloud templates; background workers and channel layers for scale
• Caching and async task support via Redis; persistent storage and migrations for relational databases

Use Cases

• Enterprise replacement or augmentation of commercial IdPs to provide SSO, delegated access, and centralized authentication for web and API applications
• Protecting internal or home-lab applications using the outpost/application-proxy model to enforce authentication and authorization policies
• Integrating existing LDAP/AD directories and provisioning flows (SCIM) to enable consolidated identity management and MFA across services

Limitations and Considerations

• Some legacy native desktop or mobile clients that embed outdated browser engines may not support the full web-based login flow; a simplified flow executor (SFE) or alternate API-key approach may be required for such clients
• Major-version upgrades can require careful attention to migrations and worker restarts; administrators should test upgrades in staging before production rollouts

authentik provides a comprehensive, protocol-rich IdP with configurable flows and deployment flexibility. It is suited for organizations that need a self-hosted, extensible SSO solution with enterprise-grade features and automation capabilities.

OAuth2 Proxy is a flexible reverse proxy and middleware component that adds OAuth2/OIDC authentication in front of web applications. It integrates with many identity providers and forwards verified identity information to your upstream services.

Key Features

• Works as a standalone reverse proxy or as an authentication middleware in front of existing proxies/load balancers
• Supports OAuth2 and OpenID Connect, including a generic OIDC provider and dedicated implementations for common providers
• Validates users by email, domain, and (for supported providers) groups
• Forwards authenticated identity details to upstream apps via HTTP headers (for example username and group information)
• Can also serve static files when used as a standalone reverse proxy

Use Cases

• Add single sign-on in front of internal tools without modifying the applications
• Protect multiple services behind a central reverse proxy using a shared authentication layer
• Gate access to dashboards and admin panels with provider-backed identity and group-based access

Limitations and Considerations

• Requires correct reverse-proxy/header configuration to avoid trusting spoofed identity headers from untrusted networks
• Provider feature support varies; group/role extraction depends on the chosen provider implementation

OAuth2 Proxy is commonly used to standardize authentication for self-hosted and internal web apps with minimal application changes. It is well-suited for environments that already rely on OAuth2/OIDC identity providers and need a lightweight authentication gateway.

Casdoor is an open-source, UI-first Identity and Access Management (IAM) and Single Sign-On (SSO) platform that provides a web-based admin console for managing users, organizations, and authentication flows. It is designed to integrate with applications via standard identity protocols and offers extensible user authentication options.

Key Features

• Web UI for user, organization, application and permission management
• SSO and federation support via OAuth 2.0, OpenID Connect (OIDC), and SAML 2.0
• Directory and provisioning integrations including LDAP and SCIM
• Multiple authentication methods including WebAuthn and TOTP-based MFA
• Built-in registration, email verification, and password recovery flows
• Public REST API and SDKs to simplify application integration

Use Cases

• Centralized login and SSO for internal apps and SaaS-style multi-tenant products
• Adding MFA and modern authentication (OIDC/WebAuthn) to existing services
• User lifecycle management and provisioning across connected systems

Casdoor fits teams that want an admin-friendly IAM/SSO solution with broad protocol support and a ready-to-use web console. It is especially useful when you need standards-based SSO plus flexible authentication methods in one deployable service.

ZITADEL is an identity and access management platform for authenticating users and securing applications. It provides hosted and custom login options, supports modern standards like OIDC/OAuth2 and SAML, and is designed with multi-tenancy in mind for B2B and CIAM scenarios.

Key Features

• Multi-tenant organizations with team and project management
• Single Sign-On with OpenID Connect and OAuth 2.x flows
• SAML 2.0 support for enterprise federation
• Multifactor authentication (OTP) and passkeys (FIDO2/WebAuthn)
• Role-based access control (RBAC) and permission management
• Self-service user registration and account management
• API-first platform with gRPC and REST APIs
• SCIM 2.0 server for automated user provisioning
• Event-sourced architecture with an audit trail

Use Cases

• Centralized authentication for web and mobile apps using OIDC/OAuth2
• B2B SaaS user management with isolated organizations and delegated admin
• Enterprise integrations via SAML and automated provisioning via SCIM

Limitations and Considerations

• Requires PostgreSQL (commonly version 14+) as the primary storage backend

ZITADEL combines standards-based authentication with strong multi-tenancy and extensibility, making it suitable for both customer-facing and internal identity scenarios. It can be operated with a hosted login or integrated more deeply via APIs for fully custom experiences.

Logto is an open-source identity and access management platform for adding authentication and authorization to web, mobile, and API-based products. It provides standards-based login, enterprise SSO, and scalable multi-tenant identity management for SaaS and AI applications.

Key Features

• OAuth 2.1 and OpenID Connect provider for apps, SPAs, and APIs
• SAML-based enterprise SSO with common external IdPs
• Multi-tenancy via organizations, including invitations and provisioning flows
• Role-based access control for global and organization-scoped permissions
• Multiple sign-in methods: password, passwordless (email/SMS codes), and social login
• Multi-factor authentication options including passkeys, authenticator apps, and backup codes
• Customizable, pre-built sign-in experience and broad SDK/framework support
• Admin console for managing apps, users, roles, and authentication settings

Use Cases

• Add secure login and token-based API access to a SaaS product
• Implement enterprise-ready SSO and org-level access controls for B2B apps
• Centralize identity for multi-app ecosystems, including AI agents and tools

Limitations and Considerations

• Running at scale typically requires operating and tuning PostgreSQL and the service stack
• Advanced enterprise/security expectations may require careful configuration of SSO, MFA, and authorization models

Logto is a strong fit when you want a modern, standards-based auth system with multi-tenancy, SSO, and RBAC built in. It helps teams ship production-ready identity features without building and maintaining custom auth infrastructure from scratch.

Tinyauth is a simple authentication middleware that sits in front of your web applications and provides a login screen or single sign-on via external identity providers. It is designed to be lightweight and easy to configure, making it well-suited for homelabs and small-to-medium self-hosted setups.

Key Features

• Adds an authentication layer in front of existing apps without modifying them
• Supports a built-in login screen with username/password
• OAuth / OIDC authentication with providers such as Google and GitHub (and others)
• LDAP authentication against a centralized directory
• Two-factor authentication support via TOTP
• Designed to integrate with popular reverse proxies such as Traefik, Nginx, and Caddy
• Ships as a single statically linked binary and is typically configured via environment variables

Use Cases

• Protect internal dashboards and admin tools behind a single login page
• Add SSO to self-hosted services that lack native authentication
• Gate access to homelab services exposed through a reverse proxy

Limitations and Considerations

• In active development; configuration and behavior may change between releases

Tinyauth provides a pragmatic way to add authentication in front of multiple services with minimal overhead. It is especially useful when you want a small, dependency-light component that works with common proxy-based deployments.

Pocket ID is a lightweight OpenID Connect (OIDC) identity provider designed for simple deployments. It focuses on passwordless authentication by using passkeys, enabling users to sign in securely without managing passwords.

Key Features

• OpenID Connect provider for authenticating users to compatible services
• Passkey-only (passwordless) authentication flow
• Designed to be simpler to operate than larger IAM suites for small setups
• Web-based admin/user interface for managing the identity provider
• Container-friendly deployment options for straightforward installation

Use Cases

• Centralized login (OIDC) for homelab and self-hosted applications
• Passwordless sign-in using hardware keys (for example, security keys)
• Lightweight alternative for small teams that only need OIDC authentication

Limitations and Considerations

• Passkey-only approach may not fit environments that require passwords or multiple auth methods

Pocket ID is a good fit when you want an OIDC provider with minimal complexity and a strong passwordless stance. It prioritizes ease of use and modern authentication for smaller, focused deployments.

Kanidm is an identity management platform that centralizes users, groups, and authentication for your applications and infrastructure. It focuses on secure defaults, simple operations, and built-in capabilities so services can offload identity and access management to a single provider.

Key Features

• OAuth2/OIDC provider for single sign-on (SSO)
• WebAuthn passkeys support, including attested passkeys for higher assurance
• Application portal for launching and accessing linked applications
• Linux/Unix integration, including offline authentication support
• SSH public key distribution for Unix systems
• RADIUS support for network and VPN authentication
• Read-only LDAPS gateway for legacy LDAP-dependent systems
• Administration via CLI tooling plus Web UI for user self-service
• Two-node high availability using database replication

Use Cases

• Replace fragmented credentials with centralized SSO for internal web apps
• Provide strong phishing-resistant authentication using passkeys
• Manage Unix fleet access with centralized identities and SSH key delivery

Limitations and Considerations

• Administrative workflows are primarily CLI-driven, while the Web UI is focused on end-user self-service

Kanidm is a strong fit when you want a unified identity provider with modern authentication (passkeys) plus practical infrastructure integrations (Unix, SSH, RADIUS). It aims to deliver enterprise-grade capabilities with a streamlined operational model and secure-by-default design.

nforwardauth is a lightweight forward authentication service written in Rust that provides a single auth middleware for reverse proxies. It validates requests, issues signed auth tokens (cookies), and redirects unauthenticated users to a simple login page.

Key Features

• Forward-auth middleware compatible with common reverse proxies such as Traefik, Caddy, and nginx
• Uses a passwd file of usernames and hashed passwords (sha-512) for credential storage
• Issues signed authentication tokens/cookies using a configurable TOKEN_SECRET
• Optional downstream header (X-Forwarded-User) to pass authenticated identity
• Configurable cookie name, domain, secure flag, port, and pass-through behavior
• Built-in, configurable rate limiter to mitigate brute-force login attempts
• Distributed as a Docker image and usable with docker-compose; simple static login UI

Use Cases

• Protect multiple self-hosted web apps behind a single authentication wall
• Integrate a simple auth layer into Traefik/Caddy/nginx setups for homelabs and small deployments
• Provide password-based access control where a full identity provider is unnecessary

Limitations and Considerations

• Authentication is limited to username/password entries in a local passwd file; no built-in OIDC/SAML/OAuth providers
• No built-in CSRF protection as of current roadmap items
• Not intended as a full SSO or enterprise identity solution; focuses on minimalism and simplicity

nforwardauth is designed for minimal operational overhead and fast response times. It is well suited to homelab and small deployments that need a simple, centralized forward-auth layer without external identity provider integrations.

AuthPortal is a lightweight, Go-built authentication gateway that provides a unified login experience for Plex, Jellyfin, and Emby users. It issues signed session cookies, offers an admin console, and can act as an OAuth 2.1 / OIDC authorization server for downstream apps. (github.com)

Key Features

• Unified login flows for Plex (PIN flow), Jellyfin, and Emby with provider-specific handling.
• Signed, HTTP-only JWT session cookies and session lifecycle management.
• Optional TOTP-based multi-factor authentication with recovery codes and per-tenant enforcement.
• Built-in OAuth 2.1 / OIDC endpoints (discovery, JWKS, token, userinfo) with PKCE and refresh support.
• Admin SPA for runtime config editing (providers, security, MFA), OAuth client management, and encrypted config backups with scheduling/retention. (github.com)

Use Cases

• Provide single sign-on for a media-focused community (Plex/Jellyfin/Emby) across internal portals and apps.
• Act as a lightweight first-party OIDC authorization server for home-lab or intranet applications.
• Centralize MFA enforcement, OAuth client lifecycle, and runtime configuration for downstream services.

Limitations and Considerations

• Designed for same-origin / intranet scenarios; production use requires proper HTTPS reverse proxy and careful key management (SESSION_SECRET, DATA_KEY).
• Relies on Postgres for user/profile storage and expects you to manage DB availability, backups, and secret rotation. (github.com)

AuthPortal is intended for self-hosting in home-lab and media community environments. It emphasizes a small runtime footprint, containerized deployment, and extensible provider support while requiring operators to follow security best practices and manage secrets and backups carefully. (github.com)

FusionAuth is a full-featured authentication and identity platform for adding login, registration, and access control to web, mobile, and API-driven applications. It provides standards-based auth flows and an admin UI for managing users, applications, and security settings.

Key Features

• Standards-based authentication and authorization using OAuth 2.0 and OpenID Connect
• SAML v2 support for enterprise SSO integrations
• Multi-factor authentication (MFA) and passwordless authentication options
• User, group, and role management with application-specific configuration
• Admin dashboard and APIs for identity management and automation

Use Cases

• Centralized login and SSO across multiple internal and customer-facing applications
• Add OAuth/OIDC-based authentication for APIs and microservices
• Enterprise integrations requiring SAML-based identity federation

FusionAuth is a practical choice for teams needing a self-hosted IAM solution with modern auth standards, multiple authentication methods, and an administrative interface for ongoing identity operations.