If you run an ASP.NET Core app directly on Kestrel, with no nginx or cloud load balancer in front, getting a real TLS certificate has always been the awkward part. For years the answer was LettuceEncrypt, which obtained and renewed a Let's Encrypt certificate inside your app. That project was archived in April 2025, and its last release targets .NET 6. So the question is open again: how do you do this now? Two things have changed, and both matter. Certificates are getting shorter ...