If curious, I did a post on that a while back. I'm settling into a new house and will pick this series back up soon.

https://nickcraver.com/blog/2016/02/17/stack-overflow-the-ar...

Web Server: IIS, Database: SQL Server, Web framework (backend): ASP.NET/MVC. Additionally: Redis, Elasticsearch, HAProxy (all on Linux). jQuery on the front end (with some TypeScript) and LESS -> CSS.