Elixir, Unraveled (José Valim interview)
May 15, 2026
A Howdy Tech Talk where I interviewed José Valim—creator of Elixir, former Ruby on Rails core team member and founder of Dashbit—about how a race condition he couldn't fix in Rails led him to functional programming, Erlang and, eventually, to creating Elixir; what senior engineers still get wrong about concurrency; and his honest take on AI coding agents.
For this edition of Howdy Tech Talks I sat down (remotely) with José Valim, the creator of Elixir. Before Elixir, José was a member of the Ruby on Rails core team; today he leads Dashbit, his own consultancy, and remains a key voice in the high-scale, functional programming community. The conversation was published as Elixir, Unraveled: watch the full interview on Howdy's site.
The bug that became a programming language
In 2010, José was deep inside Ruby on Rails, chasing a race condition he couldn't reproduce and couldn't prove he'd fixed. That single, stubborn bug pushed him toward functional programming, then Erlang, and eventually toward building something new entirely: Elixir. Today Elixir runs the backend of companies operating at massive scale, such as Discord and Pinterest, from real-time platforms to global logistics, on the same BEAM virtual machine that powers WhatsApp's Erlang backend.
The best way of solving your problem is disappearing the problem. — José Valim
What we talked about
- The origin story, from that unfixable Rails bug to shipping a new language.
- The design decisions behind the BEAM, the Erlang virtual machine that makes millions of concurrent connections on a single server possible, with the reliability it inherited from its telecom roots.
- What senior engineers still get wrong about concurrency.
- His unfiltered take on AI coding agents and what building software looks like in the AI era.
