Rock the Code 11 - José Valim on Elixir, AI Tools, Gradual Type Systems, and Being a Prolific Open-Source Contributor
Mar 12, 2026
01:53:41
José Valim is the creator of the Elixir programming language and cofounder of Dashbit, where he focuses on growing the Elixir ecosystem, the Tidewave web AI agent, and Livebook, a Jupyter-style notebook for Elixir. Before creating Elixir, he cofounded Plataformatec (acquired by Nubank) and was a core Ruby contributor.
Elixir language: https://elixir-lang.org/
Dashbit: https://dashbit.co/
Tidewave AI: https://tidewave.ai
Livebook: https://livebook.dev
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0:00 Intro
1:32 Elixir 1.20 type inference: what's new
9:15 Gradual typing vs TypeScript's approach
15:03 Typing existing Elixir code without breaking it
19:35 Set-theoretic types vs Hindley-Milner
25:06 Developer happiness: tooling and documentation
34:48 Elixir adoption: growth and decentralization
39:21 Origins: falling in love with the BEAM
45:09 Dashbit: small team, big ecosystem impact
49:18 Enabling open-source contributors
57:11 José's planning and productivity habits
1:00:20 Open source sustainability and burnout
1:08:04 NX and Elixir for machine learning
1:17:16 Elixir vs Python in the age of AI agents
1:23:28 Marketing Elixir to developers
1:29:29 Teaching as a core skill
1:34:05 BEAM vs JVM: concurrency and fault tolerance
1:43:33 Akka, virtual threads, and the BEAM scheduler
1:50:54 Where to start with Elixir
