Announcing oso (and a new blog series about Reflection in Rust)

Hey everyone!

We've been building oso - an open source policy engine for authorization that's embedded in your application.The core of oso is the Polar language for writing policies, which is a logic programming language implemented in Rust and exposed to a bunch of other languages over FFI + WASM.

We added initial Rust support for oso in v0.6. It was pretty different to the other language integrations we built, and required us implementing a runtime reflection system for Rust to drive interactions between the Polar VM and the Rust applications. We had a ton of fun building it, so we decided to write up our experiences in some blog posts. Here's the first part!

You can find documentation for oso, including a Rust version in our quickstart guide and
specific Rust documentation on our docs site or on

Some other useful links:

Source code:

Feel free to join us on Slack for any questions: or ask me here!