Arista Networks

You need to learn many open-source tools and technologies. You are expected to build features from end to end, which include creating functional/design specs, getting them reviewed, developing the product, and finally writing test cases for the same.

They have the worst indigenous language they created called TACC. Nowhere else it is used. The worst part is you need to be well-versed with the language to develop your product code. It doesn't matter which team you are in; the development is done in TACC only.

They don't have proper documentation and videos for TACC. Also, only the top 5% of higher management knows the full 95% of TACC. You have to keep running back to them if you are stuck with TACC, which makes the development slow and tiring.