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    What is Oso?

    Oso is a batteries-included library for building authorization in your application.

    Oso gives you a mental model and an authorization system – a set of APIs built on top of a declarative policy language called Polar, plus a debugger and REPL – to define who can do what in your application. You can express common concepts from “users can see their own data” and role-based access control, to others like multi-tenancy, organizations and teams, hierarchies and relationships.

    Oso lets you offload the thinking of how to design authorization and build features fast, while keeping the flexibility to extend and customize as you see fit.

    Developers can typically write a working Oso policy in <5 minutes, add Oso to an app in <30 minutes, and use Oso to solve real authorization problems within a few hours. To get started, you add the library to your application, create a new Oso instance and load an Oso policy. You can mix and match any of Oso’s authorization APIs to implement features like roles with custom policies that you write to suit your application.

    Oso is ideal for building permissions into user-facing applications, but you can check out Use Cases to learn about other applications for Oso.

    Oso currently offers libraries for Node.js, Python, Go, Rust, Ruby, and Java.

    Getting started

    To get up and running with Oso, check out the Getting Started guides in the Oso documentation.

    If you have questions, need help getting started, or want to discuss anything about the product, your use case, or authorization more generally, join us on Slack.



    Oso's Rust core is developed against Rust's latest stable release.

    Language libraries

    Oso's language libraries can be developed without touching the Rust core, but you will still need the Rust stable toolchain installed in order to build the core.

    To build the WebAssembly core for the Node.js library, you will need to have wasm-pack installed and available on your system PATH.

    Language requirements

    To work on a language library, you will need to meet the following version requirements:

    • Java: 10+
      • Maven: 3.6+
    • Node.js: 12.20.0+
      • Yarn 1.22+
    • Python: 3.6+
    • Ruby: 2.4+
      • Bundler 2.1.4+
    • Rust: 1.46+
    • Go: 1.12+




    See: LICENSE.

    Share your story

    We'd love to hear about your use case and experience with Oso. Share your story on Twitter or fill out this form for some Oso swag.




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