By latency, what do you mean? Erlang excels with Input/Output (the VM's I/O manager is well-tuned) and network applications. I think WhatsApp is latency critic

By latency, what do you mean? Erlang excels with Input/Output (the VM's I/O manager is well-tuned) and network applications. I think WhatsApp is latency critical, no user ever said it's okay to have their message show up minutes after it was sent if both parties were on a good internet connection...