Add-ons
Newest Extensions
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Undo Send Queue
Gmail-style Undo Send for Thunderbird — delay outgoing mail 5–60 seconds and cancel before it goes out .
configurable delay, undo from notification/queue, dark mode, no network, no telemetry
Table Border
Define automaticamente border=1, cellpadding=3 e cellspacing=0 na tabela HTML onde o cursor está posicionado, direto na barra de formatação da janela de composição.
Missing Attachment Warner Plus
Thunderbird's built-in reminder checks one language with a fixed list. This warns in 9 languages, lets you add your own trigger words, and only interrupts right before sending.
Iris Mail AI
A Thunderbird extension that integrates AI assistance directly into the compose window, letting users draft replies, fix grammar, translate text, and adjust tone without leaving the email client.
Markdown Paste
Paste Markdown (GitHub Flavored) into a Thunderbird compose window and see it rendered as formatted rich text instantly. Also includes a toolbar button to render/un-render the whole draft.
Sender Avatars for Thunderbird
Shows coloured sender avatars with initials in the Thunderbird message list. Falls back to Gravatar for senders with public profiles.
MinIO Filelink
CodeSnap - Generate Code Images
Turn code on any webpage into beautiful images. Select, right-click, and customize in seconds.
ThunderWrite
Auto sentence casing
Dictionary-based replacements
Superscript conversion for units and ordinals
Fraction convrsion
Degree symbol conversion
Diameter symbol conversion
Smart spacing adjustments
User-configurable settings and custom dictionary
Thunderpen
A TinyMCE-powered rich text editor for Thunderbird — replaces the built-in compose editor and adds a dedicated signature editor. Includes tables, format painter, multilingual UI. Fully self-hosted, no CDN dependency, no telemetry. Requires TB 115+.
Caveman Mode — ChatGPT, Claude & Gemini
Make ChatGPT, Claude, and Gemini speak like a smart caveman. Less filler, fewer tokens, same substance.
Isabelle markup expander
Parse Isabelle escape codes and replace them by unicode representation
Email Translator
Translates the open email to the selected language — shows translation in a split view inside Thunderbird.
Differential Folder Copy
Copies only messages that do not already exist in the destination folder, in controlled batches, between Thunderbird folders.
Vacation Responder
Automatic out-of-office reply: custom text, account(s), date window. Note: only works while Thunderbird is running.
ChromaKit - Pick Color from Any Website
All in one tool to Pick, convert, and export colors or assets from any webpage.
添付メール便
Mail Filter Alert
Monitors and filters incoming and unread emails based on user-defined keywords, displaying matches in a beautiful centralized dashboard.
NLS Mail Manager
Manage incoming Thunderbird mail locally with automatic rules, folder routing, spam word checks, attachment extension checks and Inbox scanning.
PostScriptum
Files your sent message and the replied-to or forwarded message right after sending — across accounts and servers, into folders of your choice, with tags. Everything that belongs together in one place.
To create your own collections, you must have a Mozilla Add-ons account.
