Best Self Hosted Alternatives to Microsoft Active Directory

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.

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.

LLDAP is a lightweight authentication server that provides an opinionated, simplified LDAP interface for managing users and groups. It is designed to be easy to set up and operate compared to full LDAP suites, while still integrating with many services that support LDAP authentication.

Key Features

• Simplified LDAP directory structure focused on users and groups
• Web UI for user and group management, including self-service profile edits
• Password reset via email when SMTP is configured
• Group membership support via memberOf for common LDAP filters
• Custom attributes management (for compatibility with specific integrations)
• Multiple storage backends: SQLite by default, with MySQL/MariaDB and PostgreSQL options
• Scriptable management via a GraphQL API
• Optional LDAPS support for encrypted LDAP connections

Use Cases

• Central user directory for self-hosted apps that support LDAP (for example file sync and media apps)
• LDAP backend (“source of truth”) for an SSO layer such as Authelia, Authentik, or Keycloak
• Lightweight user/group management for homelabs and small organizations

Limitations and Considerations

• Not a full-featured LDAP server by design; some advanced LDAP features and browsing tools may not work as expected
• Does not support providing password hashes for services that validate passwords locally (known incompatibility category)

LLDAP is a pragmatic choice when you need LDAP compatibility for authentication without the complexity of running a full LDAP stack. It works best as a simple user and group directory paired with other components for SSO and access control when needed.

GLAuth is a lightweight LDAP authentication server designed for development, CI pipelines, and home infrastructure. It provides an easy-to-run alternative to heavier directory services while supporting multiple configurable backends and LDAP/LDAPS endpoints.

Key Features

• LDAP and LDAPS listeners for authentication and directory queries
• Config-file backend for simple, single-binary deployments
• Pluggable/chained backends, including file-based storage, S3-backed storage, SQL via plugins, and proxying to existing LDAP servers
• Centralized management of users, groups, passwords, Linux account attributes, and SSH public keys
• Optional two-factor authentication designed to be transparent to LDAP client applications
• Suitable for lightweight directory needs across common infrastructure tools that support LDAP auth

Use Cases

• Centralizing user and group management for homelab or small server fleets
• Providing an LDAP auth endpoint for internal tools and CI environments
• Fronting or augmenting an existing LDAP directory with a proxy backend

Limitations and Considerations

• For production usage, LDAPS/TLS should be configured explicitly rather than relying on plaintext LDAP
• Some advanced directory/AD features may not be available compared to full OpenLDAP or Active Directory deployments

GLAuth is a practical choice when you need LDAP-compatible authentication with minimal operational overhead. Its backend flexibility makes it useful both as a standalone directory for small environments and as an integration layer alongside existing LDAP infrastructure.

Stackspin is an open source platform for running a value-aligned work collaboration suite you control. It bundles multiple best-of-breed open source apps behind a single login and provides centralized administration for teams.

Key Features

• Single sign-on across integrated collaboration apps
• Centralized user and access management via an admin dashboard
• One-click installation and lifecycle management of multiple apps as a suite
• Automated backups and instance monitoring for operations teams
• Integrations aimed at managed/self-hosted deployments, including hosting provider integration

Use Cases

• Non-profits and small organizations needing a full collaboration stack with one login
• Distributed research teams coordinating documents, chat, and file sharing
• Communities running shared tools (docs, tasks, passwords) with streamlined administration

Limitations and Considerations

• Available apps and integrations depend on the platform’s supported application catalog and deployment options
• Some contribution workflows may require contacting the maintainers due to anti-spam restrictions

Stackspin is a good fit when you want a cohesive open source “work suite” rather than deploying and managing each collaboration tool separately. It emphasizes simple admin operations, safer defaults, and a unified user experience across apps.

Samba is a feature-rich open source implementation of the SMB/CIFS and Microsoft Active Directory-related protocols for Linux and other UNIX-like systems. It provides interoperable file and print sharing for Windows, macOS, and Linux clients, and can integrate hosts into AD environments or run as an AD Domain Controller.

Key Features

• SMB file sharing and Windows-compatible network file services
• Network print sharing for SMB clients
• Active Directory Domain Controller functionality (Samba AD)
• Active Directory member server mode with domain integration
• Authentication and directory integration using common AD protocols (including LDAP and Kerberos)
• Scalable deployment options, including use in clustered and enterprise NAS environments

Use Cases

• Provide centralized file and print services for mixed OS networks
• Replace or complement Windows Server for SMB shares and AD domain services
• Integrate Linux/Unix servers and desktops into an existing Active Directory domain

Samba is widely used as the standard SMB server on Linux and is suitable for both small networks and enterprise deployments that require compatibility with Windows file sharing and AD-based identity management.