ZITADEL

ZITADEL is an open-source identity and access management platform for teams that need more than basic authentication. It covers SSO, MFA, passkeys, OIDC, SAML, and SCIM for SaaS products, B2B platforms, and self-hosted IAM stacks, with vendor lock-in avoided through an API-first model.

It uses strict multi-tenancy with Identity System, Organizations, and Projects, and every mutation is written as an immutable event for an API-accessible audit trail. Resources are available through connectRPC, gRPC, and HTTP/JSON APIs, with webhooks, custom code, token enrichment, RBAC, self-registration, custom branding, and hosted login.

ZITADEL Cloud and self-hosted ZITADEL run the same codebase. The stack uses PostgreSQL 14 or newer, supports zero-downtime updates and horizontal scalability without external session stores, and is licensed under AGPL-3.0 with some Apache 2.0 and MIT exceptions.