Topaz is essentially a combination of OPA (which is used as the decision engine, with full support for Rego), and a Zanzibar-style directory, which is fairly is

Topaz is essentially a combination of OPA (which is used as the decision engine, with full support for Rego), and a Zanzibar-style directory, which is fairly isomorphic to what OpenFGA has implemented. The advantage is that it's a single container image (or go binary, if that's how you want to run it), and supports a combination of RBAC, ABAC, and ReBAC. ABAC is accomplished via the Rego language, which is as "standard" as it comes in the cloud-native world.