I'm not a software engineer, but the best codebase I worked on was at Quora. I attribute this to them having several years of time to build a base that was soli

I'm not a software engineer, but the best codebase I worked on was at Quora. I attribute this to them having several years of time to build a base that was solid. That said, I found plenty of bugs, but it was just so nice to work with. Almost everything was Python. DOM, CSS, JS embedding, etc... keeping in mind this was way before Angular/React, but the system worked very similar, doing DOM diffing via a C++ service on the backend and pushing updates out over a long polling JS endpoint. On top of that the data which was read heavy went through several layers of cache that were very easy to understand (process, system, global - called L1, L2, L3 like a system as a CPU). The front-end had a "Konami code" that let you see the rendering hierarchy from the backend while viewing it from the frontend that let you also understand the caching state of each level of hierarchy that was rendered as well as all the CSS/JS handlers affecting the element, not unlike current "inspect" view of most browsers. What made this all so good? A very strong foundation that was opinionated, but which was consistent. This was ~ 2012-2014 - they had Flask as an underlying framework, and much was built out on top of Python decorators. Besides the day-to-day code - they had a bespoke packaging system, auto-scaler, and a number of other services that "just worked" - it was very different from any other startup I've worked for.