The Mail app in Nextcloud is a webmail frontend that connects to any IMAP server — including your Mailcow at xaweho. Handy if you want mail and files in one tab.
What the Mail app is (and what it isn’t)
It is:
- A webmail client inside Nextcloud — comparable to Roundcube or SOGo
- Compatible with any IMAP/SMTP server (external providers too)
It is not:
- A mail server of its own — you still need Mailcow (or another server)
- A mail client with local storage — everything stays on the mail server
Put differently: the Mail app is just the UI. The mails still live on Mailcow.
Setup for Mailcow users
In Nextcloud: click the Mail icon in the top navigation.
On first start: the account wizard:
- Email address: your Mailcow address
- Password: your Mailcow password
With a Mailcow domain and correctly configured DNS records, auto-discovery works — Mail detects the IMAP/SMTP servers automatically.
If not, manually:
| Field | Value |
|---|---|
| IMAP server | mail.<your-domain> |
| IMAP port | 993 |
| IMAP security | SSL/TLS |
| SMTP server | mail.<your-domain> |
| SMTP port | 465 |
| SMTP security | SSL/TLS |
| Username | your full email address |
Compare with our Mailcow server data reference — same setup as for any other mail client.
Setup for other mail providers
Works with any provider that supports IMAP:
- Gmail (with an app password)
- Outlook.com
- mailbox.org
- posteo.de
- 1&1, Strato, web.de, etc.
Setup as above — look up the server details with the respective provider.
What the Mail app does well
- Multiple accounts in parallel (e.g. Mailcow + Gmail)
- Search in subject, sender, body
- Rendering HTML mails
- Opening attachments (in office apps, the browser PDF viewer)
- Saving attachments to Nextcloud Files with one click
- Attaching files from Nextcloud without a local download
- Address book integration with Nextcloud Contacts
- Quick reply and inline replies
- Filters / rules (Sieve-based, if the mail server supports Sieve — Mailcow does)
- PGP encryption via the separate Mailvelope browser extension
Where it’s weaker (compared to Thunderbird / Outlook)
- Offline mode: not available, an online connection is always required
- Advanced filter UI: Sieve rules have to be written more or less by hand
- Conversation view: simpler than Gmail/Outlook
- Calendar integration in the mail view: no drag and drop from mail into an appointment (done separately in the calendar)
- Performance with very large mailboxes (>100,000 mails): noticeably slower
From our experience: great for daily use in family/club setups. Power users with 1000+ mails/day are better off with a dedicated mail client.
Setting up Sieve filters
In the Mail app → account settings → Sieve scripts.
Sieve is a standard for server-side filters — filters run on the server, not in the client. Advantage: they apply to every device that uses the account.
Example: automatically move all newsletters into a folder:
require ["fileinto"];
if header :contains "List-Unsubscribe" "" {
fileinto "Newsletter";
}We’re happy to help with more complex filter scripts — a ticket is enough.
PGP/GPG with Mailvelope
The Mail app itself has no built-in PGP. But with the Mailvelope browser extension it works:
- Install the Mailvelope extension in Chrome / Firefox
- Generate a key pair in Mailvelope
- When composing mail in Nextcloud Mail, Mailvelope detects the compose field and offers encryption
Works for PGP inline and PGP/MIME.
Saving attachments to Nextcloud
Open a mail with an attachment → click the attachment → Save to Nextcloud.
The file lands directly in your cloud storage, no download detour. Very handy for invoices, documents, photos.
Files from Nextcloud as attachments
While composing a mail → attach symbol → Attach from cloud.
You can either:
- Attach the file directly (the mail grows, the classic way)
- Insert it as a sharing link (the mail stays small, the recipient downloads from your cloud)
For large files (>10 MB), always prefer the sharing link — it spares the mail server quota.
Address book integration
While composing, Nextcloud Mail automatically suggests addresses from your Nextcloud Contacts.
When you mail a new address, you can have a contact entry created right after sending.
Multi-account setup
You can have several mail accounts in the Mail app:
- Private Mailcow account
- Work Mailcow account
- Gmail account for external communication
Each with its own inbox area, cleanly separated in the sidebar.
Frequently asked questions
Does every user get the Mail app, or is that an admin thing? The Mail app has to be installed by an admin under Administration settings → Apps. Then every user has the app and can set up their own account.
Are my mails stored in Nextcloud? No. The mails stay on the IMAP server (Mailcow). The Nextcloud Mail app is only the frontend. If you delete the Nextcloud Mail app, your mails remain on Mailcow.
Push notifications for new mails? Not directly. The Mail app polls regularly (default 5 minutes). For real push: use a dedicated mail client app on your phone (with IMAP IDLE).
Does the Mail app work with 2FA enabled in Nextcloud? Yes — only the mail password from the mail server is needed, which is independent of Nextcloud 2FA.
Forgot the mail password — how do I get back in? With Mailcow: use the Mailcow domain admin (or the self-service password reset). More in Creating and managing mailboxes.
Is there a smartphone app for Nextcloud Mail? No, a separate app doesn’t exist. On the phone: connect a regular mail client (Apple Mail, Gmail app, K-9 Mail) directly to Mailcow.
Multiple identities — is that possible? Yes. Per account you can configure several “aliases” or “send-as” identities, if the mail server supports it.
Are the mail passwords stored encrypted in Nextcloud? Yes, mail passwords are encrypted in the Nextcloud database with the server master key. For very high security requirements, still use a separate mail client.
Does Sieve always work? Only if the mail server has a Sieve service. Mailcow: yes. Gmail: no (it has its own filter mechanics). With a Gmail account in Nextcloud Mail, you use the Gmail web filters directly at the provider.
What’s next
First login as a Nextcloud admin
What to do after your Nextcloud is provisioned — login, profile, the important first settings, what we handle and what you handle.
Admin GUI overview — what you'll find where
Nextcloud's administration settings are big. Here's a tour of the sections that matter and what they do.
Creating users and groups
Create users for family, club or team, organize groups, set quotas, control login behavior.
Sharing — files with others, internally and externally
Sharing files in Nextcloud — within your cloud with other users, with groups, or externally via sharing link.