Cloud Attachment for Nextcloud

Need to send a file that is already in your Nextcloud? Thunderbird's built-in Filelink only uploads files from your computer, and most Nextcloud add-ons only insert a link. This add-on attaches the file itself.

Attach files from your Nextcloud
Pick one or more files – also from different folders – in a folder browser right in the compose window. The add-on downloads them from your Nextcloud and adds them to the email as normal attachments. Useful whenever the file has to be inside the email: invoices, contracts, forms, or recipients who cannot or will not open cloud links. You get a warning before attaching large files.

Or insert share links
For large files, insert a public read-only share link per file at the cursor (HTML and plain-text mails), optionally with password and expiration date. Existing public links are reused when no options are set.

Also a Filelink provider
Large attachments from your computer can be uploaded to a folder in your Nextcloud (default: /Mail-attachments) and replaced by a link, using Thunderbird's built-in Filelink offer. Big files are uploaded in chunks, and the toolbar button shows the progress. Existing files are never overwritten; removing the attachment cancels the upload or deletes the uploaded file.

Simple and lightweight
• Works with any Nextcloud – only WebDAV and the standard sharing API are used, no server app needed
• Thunderbird 115 or newer
• Server check before sign-in: verifies via status.php that the address really is a working Nextcloud before any password is entered
• Secure sign-in with Nextcloud Login Flow v2 – the add-on gets its own app password, no need to type your account password. Signing in with a manually created app password is also possible.
• Sign out revokes the app password on the server
• Access is requested only for your own server, at sign-in – not for all websites
• English and German user interface

Privacy
The add-on talks only to the Nextcloud server you configure. No telemetry, no third parties.

This add-on is not affiliated with or endorsed by Nextcloud GmbH. Nextcloud is a registered trademark of Nextcloud GmbH.

0.6.4 – release

• Browse your Nextcloud from the compose window and attach files as real attachments, or insert public share links (optional password and expiration date).
• Filelink provider: large local attachments are uploaded to a folder in your Nextcloud (default /Mail-attachments) and replaced by a link. Files over 64 MiB are uploaded in chunks; the toolbar button shows the upload progress.
• Removing the attachment cancels a running upload or deletes the uploaded file.
• Server check via status.php before sign-in, sign-in with Nextcloud Login Flow v2 (or an app password).
• English and German.

# Privacy Policy – Cloud Attachment for Nextcloud

*(Deutsch weiter unten)*

**Short version: the add-on talks only to the Nextcloud server you configure. It collects
nothing, sends nothing to the author or any third party, and contains no analytics.**

## What data is processed

| Data | Where it goes | Why |
|---|---|---|
| Server URL you enter | stored locally in Thunderbird | to know which server to contact |
| App password and login name | stored locally in Thunderbird, sent only to your Nextcloud server | to authenticate WebDAV and share requests |
| File and folder names of your Nextcloud | read from your server, shown in the popup, not stored (except the last opened folder path) | to let you pick files |
| Files you choose to attach | downloaded from your server into the email being composed | that is the feature |
| Share links you create | created on your server, inserted into the email | that is the feature |
| Settings (size warning, default expiry) | stored locally in Thunderbird | your preferences |

Local storage is the add-on's `storage.local` inside your Thunderbird profile. It is not
encrypted by the add-on; protect your profile as you would your mail.

## What the add-on does not do

- No telemetry, analytics, crash reporting or tracking.
- No connections to any server other than the one you configure.
- No access to your mail contents except the message you are composing, and only when you
click "Insert link" or "Attach".

## Permissions

- `compose` – insert links and add attachments to the message being written.
- `storage` – keep settings and the app password.
- Host access (optional) – requested at sign-in for exactly the server you entered, removed
again when you sign out.

## Removing your data

"Sign out and revoke app password" deletes the stored credentials, revokes the app password
on your Nextcloud and removes the host permission. Uninstalling the add-on removes all
locally stored data.

---

# Datenschutz – Cloud Attachment for Nextcloud

**Kurz: Die Erweiterung spricht ausschließlich mit dem Nextcloud-Server, den du einträgst.
Sie sammelt nichts, sendet nichts an den Autor oder Dritte und enthält keine Statistik.**

- Server-URL, Benutzername, App-Passwort und Einstellungen liegen lokal im
Thunderbird-Profil (`storage.local`, von der Erweiterung nicht verschlüsselt).
- Datei- und Ordnernamen werden vom eigenen Server gelesen und nur angezeigt; gespeichert wird
nur der zuletzt geöffnete Ordner.
- Ausgewählte Dateien werden vom eigenen Server in die gerade verfasste Mail geladen, Links
auf dem eigenen Server erstellt und in die Mail eingefügt.
- Keine Telemetrie, keine Verbindungen zu anderen Servern, kein Zugriff auf andere Mails.
- „Abmelden und App-Passwort widerrufen“ löscht die Zugangsdaten, widerruft das App-Passwort
auf dem Server und entzieht das Zugriffsrecht. Deinstallieren entfernt alle lokalen Daten.

Add-ons

Welcome to Thunderbird Add-ons.

On the go?

Cloud Attachment for Nextcloud 0.6.4

by minos33

About this Add-on

Version Information

Verzija 0.6.4 Released novembar 3, 2026 31.1 KiB Works with Thunderbird 115.0 and later