Dropbox uses Go (https://github.com/dropbox/godropbox), Rust (e.g. https://github.com/dropbox/rust-brotli) and Python on the server-side, and both Rust (https://github.com/dropbox/finderinfo-rust) and Python on the client-side.

As other commenters have noted, a lot of their Python use for large scale systems was an artifact of history and available choices at the time, but from my experience during my time there and following as an outside observer since leaving, they seem to make reasonable infrastructure and language decisions for their core product.

Go wasn't created until 2009 and Dropbox already had tons of Python code by then as well as extremely accomplished Python programmers (they hired the creator of Python only a few years later). I also don't think Go would have allowed the tight integration with, for example, OS X where Dropbox actually superimposes their icons onto your Finder icons. As far as I understand, it was only because of smart programming and use of OS X's Python / Ruby bridge functionality that they were able to do it.

Looks like they already have Rust/C++/obj-c in use, which all fill that purpose a bit better than Go would.

Go code is about ~30% more verbose than equivalent python.

Go isn't good at the system level. I.e. calls to C APIs are expensive, etc.

Why are people downvoting this? It’s a fine question to ask. I think people have been downvoting questions more lately, and it’s unfortunate.

So much downvoting for a honest question :/

Go wasn't a thing in 2007.