José Valim

José Valim grew up on Rails. He served on the Ruby on Rails Core Team, the small group that steers the framework, from 2010 until he stepped back into its alumni in 2015, and he ranks among the framework’s all-time top contributors with heavy work in the Rails 3 era. He is best known in Ruby for writing Devise, the “flexible authentication solution for Rails” that a huge number of apps still use to handle user sign-up and login.

Then he left to build something new. José created Elixir, a programming language that first appeared publicly in 2012, as a research and development project at his consultancy Plataformatec (later acquired by the bank Nubank). Elixir runs on the BEAM, the battle-tested virtual machine built for the Erlang language and known for handling huge numbers of simultaneous users without falling over. His stated goal was more extensibility and productivity on that VM, and the result carries Ruby’s warm, developer-first feel into a world built for concurrency: the same instinct as "Optimize for programmer happiness", the value David Heinemeier Hansson (DHH)’s Rails helped make famous.

These days José is Chief Adoption Officer at Dashbit, and much of his energy goes to machine learning in Elixir. He helped start Nx (Numerical Elixir), a library for the multi-dimensional arrays, called tensors, that numerical and machine-learning code runs on, and he builds Livebook, an app for interactive, shareable Elixir notebooks.

Related: David Heinemeier Hansson (DHH) · "Optimize for programmer happiness" · Yukihiro "Matz" Matsumoto