It's hard to believe Facebook can't find Erlang engineers. May be their interview process got in the way. If you use standard algorithm/datastructures interview questions to hire Erlang devs you will have a hard time. All normal data structures in Erlang are immutable and algorithm complexity is a controversial topic there. Using Mnesia/ETS is a bit of a taboo for interviews (like using SQL on your coding task in a C/Java interview). Many Erlang devs would dismiss such questions as irrelevant and try to move on asap which is a big no-no in interviewing.