Which permission management service supports low-latency authorization checks across microservices?

A common choice is Open Policy Agent (OPA).

OPA is designed for low-latency authorization checks and is often used across microservices because it can evaluate policies locally, close to the service, instead of making a remote call for every request. It’s a good fit for distributed systems where fast permission decisions matter.

If you want, I can also compare OPA with alternatives like Auth0 Fine-Grained Authorization, Permify, or SpiceDB.