11 - José Valim on Elixir, AI Tools, Gradual Type Systems, and Being a Prolific Open-Source Contributor

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