Now that you have gone through the entire playlist, I want to briefly list down the set of technologies we are using to build Commonlounge, along with a line or two about why we chose them:

1. Frontend JS Framework: We use React library from Facebook, in conjunction with Redux , which helps you manage your app state. Before you start learning Redux, I would highly recommend checking out You Might Not Need Redux written by the person who created it. Also, the best source to learn Redux is by following this Redux course of 57 very short screencast videos.
2. Styles: We use Sass preprocessor for our CSS. We also use Bourbon for common mixins like vendor prefixes, media queries etc. and the accompanying Neat for managing the grid system.
3. Backend: We use Django, along with a modified version of Django REST framework — it helps us create an internal API that the React app can use (and mobile apps will consume in the future). Why Django? Because we are very comfortable with Python and have a lot of experience customizing it. We also optimized the way we make queries through the ORM to make the site faster :). This essentially meant writing an interface similar to GraphQL but much more in tune with our needs.
4. Infrastructure: We host everything on AWS and server our web application through dockerized containers.

Hope you had some fun while going through the playlist. The best part about Commonlounge is that the playlists can keep evolving as the field changes, and I'll keep posting new tutorials/quizzes here to reflect that. Good luck!