The onion architecture, introduced by Jeffrey Palermo, overcomes the issues of the layered architecture with great ease. With Onion Architecture, the game-changer is that the Domain Layer (Entities and Validation Rules that are common to the business case ) is at the Core of the Entire Application. This means higher flexibility and lesser coupling. In this approach, we can see that all the Layers are dependent only on the Core Layers.

openam

OpenAM is an open access management solution that includes Authentication, SSO, Authorization, Federation, Entitlements and Web Services Security.

openam-.net-agent

OpenAM .Net SDK and Microsoft IIS policy agent

opendj

openicf

OpenICF (Open Identity Connectors Framework) is built to help drive development of Connectors. Connectors provide a consistent generic layer between applications and target resources.

openidm

openig

Open Identity Gateway (OpenIG) is a high-performance reverse proxy server with specialized session management and credential replay functionality.

oqtane.framework

Modular Application Framework for Blazor

oracleclient

orchardcore

Orchard Core is an open-source modular and multi-tenant application framework built with ASP.NET Core, and a content management system (CMS) built on top of that application framework.