danterm is a fast macOS terminal built in Swift with no third-party dependencies.
I like vertical tabs, which for years meant using iTerm2 on macOS.
In the LLM era the terminal is becoming more and more central to my workflow, not less. So, I decided to build my own to satisfy my own preferences.
It runs on its own Swift terminal engine -- grid, parser, renderer, and pty, with no third-party dependencies. It started as an AppKit wrapper around libghostty, but LLMs made writing the engine itself tractable, and the project doubles as a testbed for automating high-quality software with AI.
- Everything should be both keyboard- and mouse-driven
- The terminal engine should be reusable outside of danterm, embeddable by other projects
- Cross-platform
- Vertical tabs
- Split panes that inherit the current working directory
- Persistent pane alerts and macOS notifications (click a notification to focus its pane)
- Local and remote color themes
- Save, restore, and crash-recover tabs, panes, and the commands running in them
- Semantic pane states ("idle", "running command (make test)", "running agent claude (busy)") reported by shell and agent integrations
- Full control via
dantermcommand-line interface for scripts and coding agents - Remote IPC over a Tailscale tailnet (docs)
- Config file
- Drive danterm running on macOS machine over Tailnet via iPhone app (Experimental)
- Linux GTK4 app (WIP)
- And much more
Measured on a MacBookPro18,1 running macOS 26.5.2. Every terminal ran at 170x60 in Menlo 13.
kitten __benchmark__ --render, 3 reps, median MB/s as the kitten reported it.
| Test | danterm | ghostty 1.3.1 | iterm2 3.6.6 | kitty 0.48.2 |
|---|---|---|---|---|
| Only ASCII chars | 127.2 | 87.9 | 12.7 | 105.5 |
| Unicode chars | 135.3 | 113.5 | 6.6 | 103.5 |
| Unique multi-codepoint Unicode cells | 53.3 | 47.1 | 1.1 | 23.0 |
| CSI codes with few chars | 47.5 | 41.4 | 1.3 | 59.3 |
The kitten times parsing, not rendering: terminals render asynchronously, and
--render only stops them from being asked not to.
10 tabs, each running an inert sleep. Activity Monitor phys_footprint,
sampled every second for 10 seconds after a 5 second settle, median reported.
One rep, so read these as a rough ranking rather than a precise number.
| Terminal | 10 empty tabs | 10 tabs with scrollback |
|---|---|---|
| danterm | 57 MB | 248 MB |
| iterm2 3.6.6 | 167 MB | 564 MB |
| kitty 0.48.2 | 239 MB | 788 MB |
| ghostty 1.3.1 | 793 MB | 1424 MB |
The scrollback case writes 10000 full-width lines per tab. iTerm2 and kitty were capped at 10000 lines. danterm and Ghostty bound scrollback by bytes instead of lines: danterm at 16 MB per pane (it kept all 10004 rows), Ghostty at 10 MB per surface (retention not readable).
Requires macOS 26 on Apple Silicon.
Download the latest .dmg from
GitHub Releases, then move
DanTerm to /Applications. Releases are Developer ID signed and notarized, and
the whole app is an 8 MB download.
If your shell tools need them, grant DanTerm Full Disk Access and Developer Tools in System Settings under Privacy & Security.
DanTerm ships a flake and a Home Manager module: docs/integrations/nix.md.
Press Cmd+, to edit ~/.config/danterm/config.json, Cmd+Shift+, to reload it.
Every setting has a default, so a new config file holds only
{"schemaVersion": 1}.
| Key | Default | Meaning |
|---|---|---|
font.family |
system monospace | Terminal font family. Omit the key to keep the system font. |
font.size |
13 |
Terminal font size, in points. Bounded to 8 through 72. |
keyboard.optionAsAlt |
native | Use "left", "right", or "both" to send that physical Option key as terminal Alt. Omit the key for native macOS text input. |
theme.default |
"Monokai Remastered" |
Theme for local panes. |
theme.remote |
"Purplepeter" |
Theme for panes in an SSH or other remote session. |
shell.localeFallback |
true |
Give a local pane a UTF-8 LANG when it inherits none. |
tailnet.listen |
absent | Tailnet endpoint for remote IPC. See docs/tailnet.md. |
tailnet.admittedNodeIds |
absent | Tailscale node ids allowed to use remote IPC. See docs/tailnet.md. |
tailnet.enable |
true |
Set to false to keep the tailnet settings on disk with the listener closed. |
ui.alertClearMode |
"focus" |
"focus" clears pane alerts on focus, "manual" keeps them until you dismiss them. |
ui.copyOnSelect |
true |
Copy a mouse selection to the clipboard when it finishes. |
ui.unfocusedPaneOpacity |
1 |
Opacity of every pane except its tab's focused one. Bounded to 0.1 through 1; 1 dims nothing. |
Nix users can point this file at a dotfiles repository so app edits survive a rebuild: docs/integrations/nix.md.
DanTerm is a plain terminal to everything you run in it. These are the tools it does something extra with, or that need a setting to work well with it.
| Tool | What DanTerm does with it | Setup |
|---|---|---|
| zsh, bash, fish | Tracks cwd, running command, and prompt marks per pane | shells.md |
| SSH, mosh | Remote theme and a user@host label on remote panes | ssh.md |
| tmux | Needs two settings, or it eats notifications and invents others | tmux.md |
| Claude Code | Pane-control skill, plus notifications that name their pane | claude-code.md |
| Codex | Pane-control skill, plus notifications that name their pane | codex.md |
| Nix, Home Manager | Flake and programs.danterm module |
nix.md |
| DanTerm for iOS | Drives a pane over a Tailscale tailnet | tailnet.md |
A tool earns a page here when DanTerm ships code for it, or when DanTerm's behavior with it differs from a plain terminal's. Everything else just works and needs no page.
danterm doctor # Check permissions, CLI, hooks, skills, jq, and configured font.| Action | Shortcut |
|---|---|
| New tab | Cmd+T |
| Close pane | Cmd+W |
| Close tab | Cmd+Shift+W |
| Split right | Cmd+D |
| Split down | Cmd+Shift+D |
| Focus panes | Cmd+Shift+H/J/K/L |
| Zoom pane | Cmd+Enter |
| Theme browser | Cmd+Shift+B |
| Next alert | Cmd+Shift+A |
| Clear pane alerts | Cmd+Shift+. |
| Preferences | Cmd+, |
| Reload config | Cmd+Shift+, |
The app menus list all shortcuts. Rebind them in Settings > Key Bindings or the config file: docs/keybindings.md.
danterm ls
danterm tab new --cmd 'just test'
danterm pane split -h
danterm pane read --pane "$DANTERM_PANE" --lines 50See integrations/danterm/SKILL.md for all
commands and examples, and the
terminal capability contract for terminal
behavior.
bash ./dev-build.sh --no-install # Build without replacing an installed app.
just provision-worktree # Run once in a new Git worktree.
just launch-slot # Run an isolated development copy.
just test # Run the test suite.MIT