Thundervim

Vim keybindings for editing email in Thunderbird's compose window.

Write email the way you edit code: Normal / Insert / Visual modes, motions, operators, text objects, search, and paragraph reflow, all inside the Thunderbird composer, with a vim-style status line and block cursor to match. It works in both plain-text and rich-text (HTML) compose windows. In HTML, your existing formatting (quoted replies, signatures, bold, links) stays intact while you edit the text.

Requirements

• Thunderbird 151 or newer (developed and tested against 152).
• Works in both plain-text and HTML compose windows. Plain text is the most battle-tested; HTML support keeps your formatting but is newer (see Rich text (HTML)).

Install

Permanent (recommended)

Once published, install Thundervim from addons.thunderbird.net. Store builds are signed, so they survive restarts and update automatically. (Listing pending.)

Try it now (temporary add-on)

You can load the add-on without signing; it stays until you restart Thunderbird.

1. Download thundervim-<version>.xpi from the Releases page (or build it yourself, see CONTRIBUTING.md).
2. In Thunderbird: Tools → Developer Tools → Debug Add-ons (or open about:debugging#/runtime/this-firefox).
3. Click Load Temporary Add-on… and select the .xpi. For local development, build first and select dist/thundervim/manifest.json.
4. Open a plain-text compose window and start editing.

Permanent installation of an unsigned build is only possible on Developer/unbranded Thunderbird with signature enforcement disabled.

Rich text (HTML)

Thundervim works in both compose modes:

• Plain text is the most thoroughly tested. To compose in plain text, hold Shift while clicking Write / Reply, or make it the default under Settings → Composition (or per-account Account Settings → Composition & Addressing → uncheck Compose messages in HTML format).
• HTML is supported by editing the text in place while leaving existing markup alone: quote levels, signatures, bold, links, and other formatting survive as you navigate and edit. Vim itself doesn't author new rich formatting (that isn't a vim concept), but Thunderbird's own shortcuts (Ctrl-B, etc.) still work in Insert mode.

HTML support is newer than the plain-text path; if a structural edit ever misbehaves on a complex message, please file an issue.

Commands

Group	Keys
Motions	h j k l, w W b B e E, ge / gE, 0 ^ $, gg G, { }, ( ) (sentences), with counts (3w, 5j)
Find in line	f{char} F{char} t{char} T{char}, repeat with ; / , (e.g. df,, ct))
Match bracket	% (jumps between ()/[]/{}; also an inclusive motion, e.g. d%, c%)
Enter insert	i a I A o O
Delete	x, X, dd, d{motion}, D
Change	s, S, cc, c{motion}, C (cw behaves like ce)
Join	J, [count]J, and J over a Visual selection
Indent	>> / <<, >{motion} / <{motion}, >ip, and Visual > / <
Reflow	gqq / [count]gqq, gq{motion}, gqip / gqap, and Visual gq (wraps at column 72, keeps quote markers like > )
Yank / paste	yy, y{motion}, p, P
Text objects	{d,c,y}{i,a}{w W " ' ( ) b { } B [ ] < > p s}(e.g.ciw, di", ci(, daw, dip, das`); also selectable in Visual mode
Replace	r{char}, and r<Enter> to split the line (replace with a newline)
Case	~ (with count), operators gu / gU / g~ with motions/text objects (gUiw, guap), line forms guu / gUU / g~~, and Visual u / U / ~
Repeat change	. (repeats the last change, including typed text; a count substitutes the recorded one)
Search	/pat ?pat (smartcase), * / # (word under cursor), n / N to step; matches highlight while typing and persist until Esc
Undo / redo	u, Ctrl-r
Visual	v, V, then d / c / y on the selection
Multi-cursor	macOS: Cmd-Option-Down / Cmd-Option-Up; Windows/Linux: Ctrl-Alt-Down / Ctrl-Alt-Up. Adds cursors below / above; vim motions and Insert-mode typing apply to all cursors; Esc in Normal mode clears extra cursors
Leave insert	Esc
Toggle on/off	macOS: Cmd-Option-V; Windows/Linux: Ctrl-Alt-V

Counts combine with operators (e.g. 2dd, d3w). Yank/paste use an internal register, so y / p never touch your system clipboard. Nothing you edit leaves your machine.

Modes and the mode indicator

• Insert mode is the default when a compose window opens, so you can type right away. Press Esc to enter Normal mode.
• The status line at the bottom of the compose window shows the current mode and vim-style ruler with the cursor's line,column and Top / Bot / All / percentage position through the message.
• The Thundervim compose-toolbar button toggles Thundervim on/off for the current compose window. Its compact badge shows the current state (I, N, V, …).
• A block cursor marks the character under the cursor in Normal / Visual mode. Thundervim removes its status line before send and scrubs outgoing mail, so editor UI is not included in the message.
• In Insert mode the native editor handles typing (IME, spellcheck, and reply-quoting all keep working); Thundervim only intercepts the keys that leave Insert mode.
• Cmd-Option-Down/Up on macOS, or Ctrl-Alt-Down/Up on Windows/Linux, adds multi-cursors below / above the current cursor. Vim motions like w, b, j, or $ move every cursor. Enter Insert mode and type to mirror text, newlines, and simple backspace/delete edits at every cursor. Press Esc in Normal mode to clear the extra cursors.
• Any other Ctrl / Cmd / Alt chord passes straight through to Thunderbird, so Send (Ctrl-Enter), Save (Ctrl-S), and friends still work. The one exception is Ctrl-r, which is redo.

Configuration

Open Add-ons and Themes → Extensions → Thundervim → Preferences to configure:

• whether Thundervim starts enabled in new compose windows;
• the default mode (Insert or Normal);
• the enable/disable toggle chord;
• an optional two-key Insert-mode escape sequence like jk;
• the escape-sequence timeout;
• shift width for >> / <<;
• text width for gq reflow.

The escape sequence is off by default, matching vanilla vim where only Esc leaves Insert mode. Saved settings apply to newly opened compose windows.

Limitations

• No : ex-commands, marks, named registers, or macros.
• Search is a literal (non-regex) substring match and is not operator-pending (d/pat is unsupported); an empty query repeats the last search.
• . does not repeat Visual-mode operations or n / search.
• In HTML, vim edits existing text and keeps your formatting but does not author new rich formatting (bold/italic/lists) on its own.

Contributing

Bug reports, ideas, and pull requests are welcome. See CONTRIBUTING.md for the architecture, how to run the tests, and how to build the package.

License

MIT © Matthias Endler