Add-ons
Message Composition
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*cloud - FileLink for Nextcloud and ownCloud
Upload large attachments to your Cloud and send the link by email
41,508 users -
SmartTemplates
SmartTemplates offers an easy and powerful way to automatically create customized replies by auto-inserting various mail headers. Templates can be created for every mail identity, Stationery files can now be imported and used directly.
3,919 users
Most Popular See all »
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True "Send Later" functionality to schedule the time for sending an email.124,805 users -
Create and Save or Send Multiple Individual and Personalized Messages from a Draft79,530 users -
Check your emails for spelling and grammar issues79,384 users -
Switch the signature on/off or choose a new one from your predefined set.55,976 users -
Securely encrypt and upload large attachments to any Send service instance (formerly Firefox Send).55,100 users -
Uploads your large attachments to your Dropbox instead of sending them by email. This uses Thunderbird's FileLink feature.52,416 users
Top Rated See all »
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Quickly choose one of the previously selected colors for a message text1,993 users -
Thunderbird は Outlook のようにアドレス全選択からの「一括コピー」ができません。
それを実現するためのアドオンです。503 users -
Macro Template is to replace mail templates with macros for date formatting.608 users
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Default "Reply" functionality pays attention to "Reply-To" in original email64 users
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Warns if you send mail from or to a specified domain. If there are multiple accounts in your profile, you can isolate one so that you can't send mail to that domain from outside or vis versa without warning.97 users
Recently Added See all »
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Claify est une extension Thunderbird qui intègre l'intelligence artificielle Claude (Anthropic) directement dans votre client email. Résumez, traduisez, corrigez et rédigez vos emails en un clic.
Fait avec ❤️ par Supersonique Studio2 users -
Highly-customizable and performant extension for @-mentions inside Thunderbird.6 users -
GPT/Gemini/Claude対応。返信画面でワンクリック or ショートカットキーでAI返信を自動生成。トーン選択可能（前向き・お断り・カスタム）9 users -
AI-powered email assistant for Thunderbird. Write, polish, and translate emails. Get smart summaries of unread messages. Works with OpenAI, DeepSeek, or custom providers.3 users -
Check your email with Gemini AI before sending.
A Thunderbird add-on that uses Google's Gemini AI to review your emails before sending. Get intelligent feedback on spelling, grammar, tone, clarity, and potential issues.39 users
See all 268 extensions in Message Composition »
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