Authentik
MIT-core identity provider for SSO, LDAP federation, SAML, and OIDC. It unifies authentication across your entire stack. Advanced compliance features and SLA support require the Enterprise edition.
Identity & Access (IAM)
Category: Identity & Access (IAM) under Security & Privacy
Keycloak
The open-source standard for Identity and Access Management (IAM), offering complete sovereignty over user data, federation, and SSO infrastructure without per-user licensing costs.
Zitadel
AGPL-3.0 IAM platform from Switzerland. SOC 2 Type II and ISO 27001:2022 verified on the SaaS tier; self-hosted edition has no MAU limits, B2B multi-tenancy and SAML included.