Stack Overflow: one of the world's largest Q&A services built with C# and ASP.NET

Stack Overflow is a public example of how a C# monolith with disciplined caching can handle traffic at a world-class scale. Nick Craver, in the Stack Overflow: The Architecture series, describes the stack: ASP.NET MVC, MS SQL Server, Redis, Elasticsearch, and public performance figures on nine web servers with substantial headroom. The team deliberately chooses proven technology and vertical scaling instead of premature microservices. For an enterprise customer, this is a reference point: the performance ceiling of a C# backend is higher than most business applications need, and architectural discipline matters more than changing languages.