Zellij
Zellij is a modern Rust-based terminal multiplexer with floating panes, built-in layouts, and a plugin system — a friendlier alternative to tmux.
Zellij is a terminal multiplexer written in Rust that aims to be more approachable than tmux out of the box. It has discoverable keybindings, built-in layout files, floating panes, session locking, and a WebAssembly-based plugin system. It targets the same workload as tmux — splitting one terminal into many — but with modern defaults.
Why it matters
Most developers try tmux, bounce off the config surface, and either power through or look for something gentler. Zellij sits in the "gentler" slot: you get a visible status bar showing the current keybindings, a sane default layout language (KDL files), and useful features (floating windows, session locks) without plugin archaeology.
For agentic coding workflows, Zellij is a common choice to run several Claude Code or Codex CLI sessions in one place. SpaceSpider covers the same use case with a GUI-first grid layout and per-project spaces.
How it works
Zellij runs a server per session and connects clients to it. Sessions contain tabs, tabs contain panes, and each pane is a PTY running a command (usually your shell). Layouts are declared in KDL and can be loaded with zellij --layout my-layout.kdl, which is powerful for reproducible dev environments.
Distinctive features:
- Floating panes — overlay on top of the tiled layout
- Session locking to prevent accidental keybinding collisions
- Plugin system in WebAssembly (plugins can be written in Rust, Go, Zig, etc.)
- First-class mouse support
- Swarm of defaults rather than empty config
How it's used
Typical Zellij usage:
zellijto start a new session,zellij attachto resume- Layout files checked into a repo so
zellij --layout ./layout.kdlspawns the full dev stack (server, test watcher, shell) - Plugin-based enhancements like a file tree or task runner
- Pair with AI coding CLIs for parallel work
Related terms
- tmux — the incumbent Zellij is often compared to
- Terminal multiplexer — the broader category
- Warp — a GUI-first alternative
- Grid layout — SpaceSpider's GUI equivalent
- PTY — what backs every Zellij pane
FAQ
Should I switch from tmux to Zellij?
If tmux config has been a friction point for you, Zellij is worth trying — the defaults are better for beginners. If your tmux muscle memory is deep and your config works, there's no urgent reason to switch.
Does Zellij work on Windows?
Not natively. Zellij is Unix-focused. On Windows, SpaceSpider uses ConPTY directly; see install-windows.
Related terms
- Agentic codingAgentic coding is software development where an LLM-powered agent plans, edits, runs, and verifies code on its own using tools, not just autocomplete.
- AI pair programmingAI pair programming is a collaboration style where an LLM assistant sits alongside you, suggesting code and reviewing changes in real time as you work.
- ANSI escape codesANSI escape codes are control sequences that terminals interpret for colors, cursor movement, and screen clearing — the language of every modern CLI UI.
- Autonomous agentAn autonomous agent is an AI program that perceives, decides, and acts on its own toward a goal — the architecture behind modern coding CLIs.
- CheckpointA checkpoint is a saved snapshot of file state that lets you roll back an AI coding agent's changes to a known-good point.
- Claude CodeClaude Code is Anthropic's official command-line agent that plans, edits, runs, and verifies code across your repo using Claude models and tool use.