It depends on your definition of real time. Erlang is quite popular in real time ad exchanges. Lack of garbage collection pauses give more predictable latency than some languages. It is considered “soft” real time, though.

When things need to be really fast and predictable, then C++ was popular, sometimes supervised by Erlang. That is a pretty good approach, isolating the pieces that need to be fast. Now speeds are such that things are done in silicon.

We wrote an embedded “logo inserter” box for the broadcast television industry in a mixture of Erlang and C++. The C++ handled the low level processing: pull a frame from a Blackmagic SDI interface, add an image, send it out another interface, 60 frames per second. Erlang handled everything else, and restarted the C++ if it should crash in time for the next frame. Bulletproof.

IMO yes! It’s possible to treat offers as processes & index them to get really fast matching. Use commanded if you need event-sourcing for auditability.

Does Elixir with Phoenix is good choice for real-time stock trading systems ?

Depends on what you mean by this. I’ve heard success stories with c++ and erlang (c++ handled computations, erlang handled some networking). And some experiments with erlang + rust (now rust handles the computations).

I don’t quite see how phoenix fits in a trading system, though.

hmm…yes, we think it’s a good choice for trading system. we wrote https://chaince.com as mentioned above by @gonglexin (and thank you so much ) based on pure elixir/phoenix/OTP infrastructure.

we’re using phoenix channel with websocket as order submission and trading reports system, it’s very fast. we think it can be called “real time”.

as to the High Availability, it’s just the pros of OTP. there’re 12 nodes in our cluster, and the whole cluster can be rolling restarted any time we like, without any service interruption.

“elixir is a good thing, maybe the best of things, and no good thing ever DIES”

Take a look at https://chaince.com/, it’s a crypto exchange which written by Elixir.