facebook chat was originally written in erlang.

http://www.erlang-factory.com/upload/presentations/31/Eugene...

I doubt they'll have any trouble at all integrating.

I believe that the reason they switched away from Erlang, though, was that nearly nobody in the company (besides the team that made the prototype) knew the language. In other words, they switched away because they had trouble integrating Erlang into their processes, and instead chose to rewrite it using tools everyone else was more familiar with.

This, then, is basically recreating the same problem they had before, just with 40 or so more engineers who are on the "Erlang" side of the vote.

Yariv Sadan is already there, though. That plus the WhatsApp people makes for a pretty intimidating group of erlangers.

edit: Just found out Yariv left. Still, Facebook was using ejabberd, and WhatsApp built their business around ejabberd.

PHP is not the only language in use at Facebook right now...

https://github.com/facebook

They invented Thrift, I think they'll figure it out.

Of all Facebook's accomplishments why is Thrift the one that you think makes this a non-issue?

They literally built it to solve problems like this. From the project page, it was designed to provide "scalable cross-language services development".

Service oriented architecture, and avoiding or porting fat client libraries. Standard stuff.

they will do what comes naturally - take five years write a dual erlang php vm in D and then open source it randomly a year or so late.

The backend is a mix of things.