José Valim (born 1986) is a Brazilian software developer who created Elixir. His background in Ruby on Rails and focus on developer experience brought Erlang’s powerful runtime to a broader audience.
Ruby Background
Valim was a member of the Ruby on Rails core team and created several widely-used Ruby gems including Devise (authentication). His experience with Rails shaped his understanding of developer experience and productivity.
Creating Elixir
While exploring concurrency solutions, Valim discovered Erlang’s powerful runtime but found its syntax and tooling challenging. He created Elixir to provide modern developer ergonomics while leveraging the battle-tested BEAM virtual machine.
Design Philosophy
Elixir reflects Valim’s priorities:
- Developer productivity: Clear syntax and good error messages
- Extensibility: Macros allow extending the language
- Compatibility: Full interop with Erlang libraries
- Tooling: First-class build tools, testing, and documentation
Phoenix and LiveView
Valim has been instrumental in Phoenix framework development and created LiveView—a paradigm for building real-time web applications that render on the server, avoiding JavaScript complexity while maintaining interactivity.
Community Building
Valim actively grows the Elixir community through conference talks, documentation, and Elixir Forum engagement. His accessible communication style helps make functional programming less intimidating.