How do you support 450 million users with only 32 engineers? For WhatsApp, acquired earlier this week by Facebook, the answer is Erlang, a programming language developed in the ’80s that is finally having its moment in the spotlight.

But with other languages starting to co-opt its ideas, does Erlang have a future?

Erlang was developed by Swedish telecom giant Ericsson over 25 years ago, and now it’s finding a home at messaging apps like WhatsApp and TigerText. Even Facebook was singing the language’s praises when it used Erlang to launch Facebook Chat back in 2009–the same year it turned down the job application of WhatsApp cofounder Brian Acton.

“With Erlang you could build a messaging app with many connected users and not worry about how they communicate,” says Chad DePue, CTO of Whisper, an app for anonymous posts that has opted to use the language. Instead, he says, “You can worry about creating a great app.”

Ericsson engineer Joe Armstrong developed Erlang with the logic of telecommunications in mind: millions of parallel conversations happening at the same time, with almost zero tolerance for downtime. Other programming languages can only give the illusion of managing all those conversations–some have gotten very good at keeping up appearances, but they aren’t natural “multi-taskers.” Erlang, in contrast, loves to multithread or “juggle” in this way–got a another spinning plate? Toss it over!

“The language is very expressive,” says Igor Clark, a creative technologist. “You can talk at a high level and do quite a lot with its few key concepts.”

In practical terms, that initially made Erlang very good at efficiently executing commands across processors within a single machine. Fast-forward to 2014, and it’s making Erlang very good at executing an even more bewildering volume of commands across the global networks of servers we have come to know as “the cloud.” For use cases in gaming, financial services, and anything that mimics the behavior of a real-time auction, that speed and reliability, at massive scale, is absolutely essential.