The Duende.BFF (Backend for Frontend) security framework packages up guidance and the necessary components to secure browser-based frontends (e.g. SPAs or Blazor WASM applications) with ASP.NET Core backends.
Duende.BFF is included in IdentityServer Business Edition or higher. The same license and special offers apply.
The source code for the BFF framework can be found here. Nuget here. Samples here.