Several fintech companies use it to power core logic, with or without phoenix, so it's used for general purpose computing where speed, resiliency, and parallel execution are important. I've seen hints that people are using it to run crypto trading bots, but idk how common that really is.

I think a few companies use Elixir to power their web crawling/scraping tools. This makes intuitive sense as a good candidate for the process supervisor and parallel work architecture OTP encourages.

Nerves (embeddable Elixir) has come a long way. I switched to Nerves for some Raspberry Pi projects and the amount of time I waste dealing with hardware/config has gone to nearly zero. I am a hardware novice and was able to setup flashing firmware over-the-air updates to the Pi with very little effort. I'm sure the companies that use Nerves in production have more to say about it.

I'm not very tuned into the updates to Scenic, a project for display/UI on embedded screens, but it looks like they've hit some big release/stability milestones.

Phoenix is the way to go for web interfaces, and is an excellent toolset, so alternatives haven't been demanded. For more lightweight http people usually reach for Plug, a key building block of Phoenix, if you won't need the full bird.

I guess it depends on your definition of useful. I've been using it since 1.4 to do things like:

- PBX configuration (e.g. dialplan and routing)

- email monitoring (e.g. monitor multiple email accounts and multiple folders on those accounts)

- interacting with API's (e.g. creating a supervision tree that has multiple API accounts making requests)

- processing huge CSV files in chunks and storing them in a database

Of course you can add Phoenix on top of these to make them more useful.

Knowing the number of people doing IoT stuff with nerves, i highly doubt it is still the case.

I’m writing a gameserver in it using Elixir without Phoenix. I’m using cowboy (erlang webserver) for websockets and redis for persistence.

You can pretty easily opt-in on specific phoenix libraries one by one and pick any you like and omit those you don’t.

The “phoenix app” type stuff is just a convention over configuration thing, but unlike something like Rails, it’s perfectly doable to pick and choose the libraries you want and install these later when you need them, or remove them when you don’t.

The functional approach to Phoenix makes it really easy to substitute things without breaking other things.

You don't have to use phoenix at all for most things, but if you're speaking HTTP, you may as well.