A multitenant library for .NET Core:
https://www.finbuckle.com/MultiTenant
In the .NET Core 2 era the older multitenant libraries like Saaskit ceased working with changes to the ASP.NET Core runtime. Finbuckle.MultiTenant fills this gap and isn't limited to ASP.NET Core use cases. It emphasizes the Options pattern instead of separate app pipelines per tenant. Also includes components for per-tenant data isolation with EF Core without having to pollute your code with a bunch of "where" conditions.