For any application that is essentially a piece of middleware linking together external calls (APIs, LLM calls, database queries), please ensure you have connection reuse/pooling on those requests
Probably one of the easiest performance improvements you can make
In Node.js, you can often do this by setting a custom HTTP agent with keepAlive: https://nodejs.org/api/http.html#class-httpagent
(from https://x.com/daniellockyer/status/1980956185571230140)