[option]

facebook is not a tech company. What new tech did it invent? It is exploiting human psychology for advertising purposes using previously existing tech

[mmanfrin]

React, yarn, cassandra.

Looking at the first page of your comment history, it seems a good third of your comments get downvoted. It may be wise to reread the HN guidelines:

https://news.ycombinator.com/newsguidelines.html

[ldarby]

https://engineering.fb.com/

[satnam14]

PyTorch. It's better than Tensorflow