Mise Runtime Manager

mise — Polyglot Runtime Version Manager

Overview

mise (formerly rtx) is a fast, polyglot runtime version manager written in Rust. It's a drop-in replacement for asdf with better performance, a simpler config format, and built-in support for environment variables and task running. Use it to manage Node.js, Python, Ruby, Go, Java, and 200+ other runtimes per-project.

When to Use

• Switching between multiple runtime versions across projects
• Replacing nvm, pyenv, rbenv, or asdf with a single tool
• Declaring runtime versions in .mise.toml for reproducibility
• Running project-specific tasks without a Makefile
• Setting environment variables scoped to a directory

Installation

# macOS
brew install mise

# Linux / curl
curl https://mise.run | sh

# Activate in shell (add to ~/.zshrc or ~/.bashrc)
eval "$(mise activate zsh)"
# or
eval "$(mise activate bash)"

# Verify
mise --version

Key Patterns

Declaring runtimes per project

# .mise.toml (project root)
[tools]
node = "22.3.0"
python = "3.12.3"
go = "1.22.4"
ruby = "3.3.2"

[env]
DATABASE_URL = "postgres://localhost/myapp_dev"
NODE_ENV = "development"

[tasks.dev]
run = "npm run dev"

[tasks.test]
run = "pytest tests/"

Installing and switching runtimes

# Install the version declared in .mise.toml
mise install

# Install a specific version globally
mise use --global node@22

# List installed versions
mise list

# Show current active versions
mise current

# Run a command with a specific version
mise exec node@18 -- node --version

# Search available versions
mise ls-remote python

Using mise as asdf replacement

# mise reads .tool-versions files too
cat .tool-versions
# nodejs 22.3.0
# python 3.12.3

# Works without any migration — just run:
mise install

Environment variable management

# .mise.toml
[env]
# Loaded automatically when entering the directory
AWS_PROFILE = "staging"
RAILS_ENV = "development"

# Dynamic values via shell
_.file = ".env"          # source a .env file
_.path = ["./bin"]       # prepend to PATH

Task runner

# Define tasks in .mise.toml [tasks] section
# Run them with:
mise run dev
mise run test
mise run build -- --watch   # pass extra args

# List all tasks
mise tasks

Shims vs PATH

# mise uses PATH modification (faster than shims)
# But shims are available for tools that need them:
mise settings set experimental true
mise generate shims

Common Pitfalls

1. Forgetting to activate: eval "$(mise activate zsh)" must be in your shell config, not just run once.
2. Global vs local: Use mise use --global for system-wide defaults and mise use (no flag) for project-local overrides.
3. Plugin not found: Run mise plugins install <name> if a tool isn't recognized.
4. Legacy .nvmrc / .python-version: mise reads these by default — no migration needed.
5. PATH ordering: mise prepends to PATH; if another version manager is also active, conflicts may occur. Remove the old one from your shell config.

Related Skills

• devbox-environments — Nix-based isolated dev environments (heavier isolation)
• earthly-builds — reproducible builds with container isolation
• nix-reproducible-builds — full Nix ecosystem for reproducibility

GitNexus Index

domain: developer-tooling
maturity: stable
complexity: low
runtime-support: node, python, ruby, go, java, rust, elixir, erlang, 200+
config-file: .mise.toml, .tool-versions
replaces: asdf, nvm, pyenv, rbenv, sdkman