Open Source Microsoft Entra ID Alternatives

Keycloak adds authentication to applications and secures services with minimal effort, so a team never has to store users or write a login flow of its own. Credentials, sessions and account recovery move out of the application entirely, which is where most of the security bugs in homegrown auth tend to live.

Beyond sign-in, the server covers user federation, strong authentication, user management and fine-grained authorization. The project publishes an operator package for Kubernetes and tracks open source best practice and security scorecard ratings in public, both of which matter for something sitting on the critical path of every login.

Running and working on the server follows a short set of paths.

• Distribution start: download a release, unzip it and run the kc script in development mode.
• Container start: the published image from the project registry starts the same way with one command.
• Building from source: a separate guide covers compiling the server for contributors.
• Testing: guides exist both for running the test suite and for writing new tests.
• Related projects: client libraries, quickstarts and a Node.js adapter live in their own repositories.

Help arrives through documentation, a mailing list for general questions and chat channels split between user help and design discussion, while security vulnerabilities follow a documented disclosure process instead of the public issue tracker. Contributors are asked to read the guide and the code of conduct first, and joining a maintainer area is offered as a way to shape where the project goes.

Single sign-on usually arrives as a hosted service with your directory inside it. Authentik is the identity provider you run yourself, sitting between users and every application they log into and issuing the assertion or token each one expects, so accounts live in one place instead of being duplicated across a dozen services.

Protocol coverage is the practical reason to reach for it. SAML, OAuth2 and OIDC serve modern web applications, while LDAP and RADIUS reach the older software and network equipment that never learned either. The same project is designed to scale from a small home lab to a large production cluster without changing tools along the way.

Installation follows the size of what you are running.

• Docker Compose: the recommended route for small and test deployments.
• Kubernetes: an official Helm chart is maintained for larger setups.
• AWS CloudFormation: official templates deploy the stack on AWS.
• DigitalOcean Marketplace: a one click app image for a quick managed host.
• Enterprise offering: a paid tier aimed at organizations replacing an existing provider such as Okta, Auth0, Entra ID or Ping Identity.

The repository carries separate licenses for the core, the website and the enterprise directory, so check which one covers the part you intend to modify. Developer documentation explains local build environments, testing your changes and the contribution process, and there is a dedicated security policy for reporting vulnerabilities rather than filing them as public issues.

Teams outgrow simple authentication the moment they start selling to other companies. ZITADEL is an open source identity and access management platform built for that point, giving SaaS products, B2B platforms and self-hosted stacks single sign on, MFA, passkeys, OIDC, SAML, SCIM and a multi-tenancy model in one deployment.

The architecture pairs a relational core with an event-driven design where every mutation is written as an immutable event, so the audit trail is a complete stream you can read through the API or push to outside systems with webhooks. Tenancy runs from the identity system down to organizations and projects, with isolated data and policy scoping at each level.

Everything the platform does is reachable over a typed interface.

• API-first surface: every resource and action is exposed over connectRPC, gRPC and HTTP JSON APIs.
• Authentication breadth: passkeys, OTP by app, email or SMS, LDAP, social and enterprise identity providers, and machine to machine flows.
• Actions: webhooks and custom code enrich tokens or run at defined points in a flow.
• Provisioning: a SCIM 2.0 server and role retrieval cover onboarding and authorization for enterprise customers.
• Self-service: registration with email and phone verification, an administration console, and branding set per organization.

Self-hosting runs on PostgreSQL 14 or newer and installs through Docker Compose or Kubernetes, with zero-downtime updates and no external session store to scale horizontally. The hosted service runs the same codebase, so moving between the two is not a change of product.