mise (formerly rtx) is a modern reimagining of asdf, written in Rust for speed. It's backward-compatible with asdf plugins and .tool-versions files, but adds two big features: built-in environment variable management (like direnv) and a task runner (like make or just). That makes it a single tool covering three jobs that previously needed three separate utilities.
Crucially, mise avoids shims by default and instead modifies PATH directly, which removes a class of confusing behavior and makes it noticeably faster. Configuration lives in a mise.toml file:
[tools]
node = "20"
python = "3.12"
[env]
DATABASE_URL = "postgres://localhost/app"
[tasks.test]
run = "npm test"You can then run mise install to set up everything and mise run test to execute tasks. Because it consolidates version management, env loading, and task running, mise has rapidly gained popularity as a replacement for the asdf + direnv + make stack. It's especially attractive for new projects that want one cohesive, fast tool.