One disclosure up front: I created NestJS and my team builds Observe, so this comparison has a clear point of view. The statements about the other tools were checked against their documentation in September 2026; those details can change, so verify them for your own setup. Every monitoring tool can trace a NestJS app. Only one of them was built from inside the framework, and that changes what a trace can show you. That's the short version of this whole post. The four realistic options for ...