The Admin OIDC Authentication module for HostBill enables secure and centralized authentication for staff members using an external OpenID Connect (OIDC) or OAuth2 identity provider. With this integration, administrators can log in to the HostBill admin area using credentials managed by a trusted identity provider, allowing organizations to unify authentication across multiple internal systems and improve overall security. To ensure uninterrupted access, the module includes a fallback mechanism that allows administrators to log in using the standard HostBill authentication method if the external identity provider is unavailable or if local credentials are required for recovery or emergency access. The module can also automatically create missing staff profiles when a user authenticates through the identity provider for the first time. New accounts are generated based on a predefined staff template, ensuring consistent permissions and configuration for newly onboarded administrators. Additionally, the module supports synchronization of staff groups with the OAuth2/OIDC provider. This allows role assignments and access levels in HostBill to reflect the group structure defined in the external identity system, helping organizations maintain consistent access policies and simplifying user management.