Oso is a provider of an authorization system designed to simplify the process of managing access controls in applications. Their platform offers a battery-included approach to building authorization by providing features like roles, attribute-based access control, and more, all programmable through a simple library that can be integrated into existing applications. This allows developers to focus on building core features while ensuring robust security practices are in place. Oso aims to make authorization dead simple for developers, streamlining the implementation of complex security requirements.