TemplateWing

An easy-to-use template management add-on for Mozilla Thunderbird (128+).

Save and reuse email templates — including file attachments — directly from the compose window.

Screenshots

Template selection	Context menu

Manage templates	Template editor

Features

• Rich text editor — Create templates with bold, italic, underline, lists, headings, and quotes
• File attachments — Attach files to templates; they are stored with the template and added automatically when inserting
• One-click insert — Insert templates via the toolbar button in the compose window or the right-click context menu
• Subject, recipients & insertion mode — Set a default subject, To/Cc/Bcc addresses, and choose whether the template appends to or replaces the current message body
• Categories — Organise templates into categories and filter by them in both the popup and the options page
• Variables — Use {DATE}, {TIME}, {DATETIME}, {YEAR}, {WEEKDAY}, {SENDER_NAME}, {SENDER_EMAIL}, {ACCOUNT_NAME}, and {ACCOUNT_EMAIL} in subject or body; they are resolved on insert. Click a variable chip in the editor to insert it at the cursor
• Keyboard shortcuts — Insert your first 9 templates with Ctrl+Shift+1 – Ctrl+Shift+9 directly from the compose window
• Recent templates first — The popup sorts by most recently used, so your go-to templates are always at the top; the options page shows a usage count per template
• Import / Export with merge modes — Back up all templates as a JSON file and restore or share them on any device. On import, choose to add all, skip duplicates, or update existing by name, with a pre-import validation summary
• Recipient validation — To, Cc, and Bcc fields are validated on save so typos are caught before insertion
• Paste sanitization — Toggle "Paste as plain text" in the editor toolbar to strip formatting from pasted content
• Duplicate name check — Prevents saving a template with the same name as an existing one
• Attachment guardrails — Large-file warnings per attachment and total size indicator; per-file error handling during insertion
• Storage schema versioning — Automatic data migration keeps templates intact across add-on updates
• Save from email — Right-click any message in the message list → Save as Template to create a template pre-filled with subject and body
• Dark mode — Follows the system colour scheme automatically
• Localized — Full English and German localization; community translations for French, Spanish, Italian, Portuguese, and Dutch

Installation

From Thunderbird Add-ons (ATN)

1. Visit the TemplateWing page on Thunderbird Add-ons
2. Click Add to Thunderbird

Manual installation

1. Download the latest .xpi file from the Releases page
2. In Thunderbird: Menu (≡) → Add-ons and Themes (Ctrl+Shift+A)
3. Gear icon (⚙) → Install Add-on From File… → select the .xpi file

Usage

1. Open a new compose window
2. Click the TemplateWing icon in the toolbar to see your templates
3. Click Insert to apply a template — or use Ctrl+Shift+1–9 for the first nine
4. Click Manage Templates… to create, edit, or delete templates

Templates can also be inserted via the right-click context menu in the compose body.

To create a template from an existing email, right-click a message in the message list and choose Save as Template.

Development

Load as temporary add-on

1. Open Thunderbird → Menu (≡) → Add-ons and Themes (Ctrl+Shift+A)
2. Gear icon (⚙) → Debug Add-ons
3. Load Temporary Add-on… → select manifest.json
4. Click Inspect next to the add-on for console/debugging

Reload after changes by clicking Reload on the Debug Add-ons page (no restart needed).

Build XPI

powershell -ExecutionPolicy Bypass -File build-xpi.ps1

This creates templatewing-<version>.xpi in the parent directory.

Alternatively, on any OS with zip installed:

zip -r ../templatewing.xpi manifest.json background.html background.js \
  LICENSE modules/ popup/ options/ images/ _locales/ \
  -x ".*" -x "*.md" -x "build-xpi.ps1" -x "tests/*" -x "scripts/*" \
  -x "package.json" -x "node_modules/*"

Project structure

manifest.json               — Extension manifest (Manifest V2)
background.html             — Background page (loads background.js)
background.js               — Context menu, storage listeners
modules/template-store.js   — CRUD operations over storage.local
modules/template-insert.js  — Variable replacement, nested templates, insertion
modules/validation.js       — Recipient/import validation helpers
popup/popup.html|css|js     — Compose-action popup (template list & insert)
options/options.html|css|js  — Options page (template editor)
images/                     — Extension icons (SVG source + 16/32/64/128 PNG)
_locales/{en,de,fr,es,it,pt,nl}/ — Localization strings
tests/                      — Unit tests (Node.js built-in test runner)

No build step, no bundler, no external dependencies — just vanilla ES6 modules.

Privacy

TemplateWing stores all data locally on your device using Thunderbird's built-in storage API. No data is collected, transmitted to external servers, or shared with third parties.

License

Mozilla Public License 2.0

Contributing

Found a bug or have an idea? Open an issue — constructive feedback is always welcome!