Aserto.com makes it easy to add fine-grained, policy-based, real-time authorization to applications. It's a centralized system that supports Open Policy Agent and the Google Zanzibar data-centric model for ultimate flexibility.
Aserto handles the heavy lifting required to achieve secure, scalable, high-performance authorization with support for every authorization model, including RBAC, ABAC, PBAC, and ReBAC. https://www.aserto.com/