sinatra-ruby-idp VS omniauth-osso

We’ll also make use of Osso’s mock IDP and demo instance, especially when we get into multi-tenancy. You’ll still want to register with an IDP for a developer account in order to have access to an IDP for a second tenant - we recommend an Okta developer account.

We don't have definite plans to build a full-featured IDP, but we did build a Mock IDP we use in CI, QA and demos that could possibly be a starting point for your purposes? Other OSS IDPs include Keycloak and Gluu Server if you wanted to check those out!

https://github.com/enterprise-oss/sinatra-ruby-idp

Osso provides an open source web app that you can use to implement SAML SSO in your Rails app. Osso handles multi-tenant SAML much like we just built in the previous section. But it also provides SAML configuration persistence and an intuitive UI to onboard customers, generating bespoke documentation for each customer to integrate your app in their IDP. In short, Osso solves all of the challenges that the previous libraries don't address. Osso provides the last 10% of a scalable SAML SSO integration that you'd normally need to implement yourself, while saving your engineering team time. Your app consumes Osso using an OAuth2 authorization code grant flow, and Osso provides omniauth-osso to make consuming Osso in your Rails app incredibly simple.