I was fortunate enough to attend ElixirConf 2019, and I wanted to give a list of my favorite presentations I saw while there.
Beyond LiveView: Building Real-Time Features with Phoenix LiveView, PubSub and Presence by Sophie DeBenedetto
Sophie showed how to tie together several Phoenix technologies to build a real-time chat app.
Nerves Project Day 2 Morning Keynote by Justin Schneck
Justin had a really impressive Nerves demo tying 11 Raspberry Pis together to distribute slice up a large Scenic display and send it to a grid of smaller displays. He also showed off a lot of production grade IoT features of NervesHub, which I'm glad you can self-host.
Writing an Ecto Adapter Introducing MyXQL by Wojtek Mach
Wojtek walked through the process of building a new Ecto adapter, which is something I might be doing soon at work. There's some good bits that show how Elixir's binary pattern matching make it easy to parse binary data, and usage of gen_tcp. Wojtek also has a good series of blog posts on the same topic.
Beam Extreme: Don't Do This At Home by Miriam Pena
Miriam showed a series of different tricks you might use to speed up bottlenecks in your code. She illustrated lost of obscure corners of the BEAM that you might not use every day, along with appropriate warnings about that problems they might cause.
Mint - Disrupting HTTP Clients by Andrea Leopardi
Andrea described the problems that the new Mint HTTP client solves, and some of it's future roadmap. He also talks about the flexibility that Mint gives uses by not prescribing any particular process architecture.
You can view the full playlist of ElixirConf presentation videos on YouTube.