Nextcloud's external storage feature lets you mount remote SFTP servers directly into your file browser. No syncing, no duplicating data, no extra clients. Just a folder that happens to live on a server somewhere else.
SFTP is the most universal protocol for this. Every hosting provider supports it, every operating system speaks it, and it's encrypted by default. That makes it a solid choice for connecting Nextcloud to offsite storage in a GDPR-compliant EU datacenter.
This guide walks through connecting Nextcloud to an SFTP datastore on remote-backups.com. The whole process takes about five minutes.
Key Takeaways
- Nextcloud's built-in External Storage app supports SFTP natively — no plugins needed
- SSH keys are generated directly in Nextcloud's admin form, no command line required
- Remote SFTP storage appears as a regular folder in Nextcloud Files
- Works with Nextcloud desktop and mobile clients automatically
- Best suited for archives and offsite copies, not primary high-frequency storage
Why Use External SFTP Storage?
The 3-2-1 backup strategy says you need at least one copy of your data offsite. Nextcloud's external storage makes that easy. Mount a remote SFTP folder, move files into it, and you have geographic separation without managing a second system.
It's also useful when you're running out of local disk space. Instead of buying more drives, offload archives and infrequently accessed files to remote storage. They stay accessible through the same Nextcloud interface.
For EU-based users, storing data in a GDPR-compliant datacenter matters. An SFTP datastore on remote-backups.com keeps your files in Germany, with clear data processing terms. No guessing about where your data ends up.
SFTP is a good fit here because it works everywhere. Unlike proprietary APIs or vendor-specific connectors, SFTP is a standard. If you ever switch providers, the protocol stays the same. We recently made SFTP storage generally available for all accounts on remote-backups.com.
Prerequisites
What You Need
- Nextcloud instance with admin access
- SFTP connection details from the dashboard (host and username)
Step 1: Enable the External Storage App
Nextcloud ships with the External Storage Support app pre-installed, but it's not always active.
Go to Apps in the top-right menu. Search for "External storage support." If it shows "Enable," click it. If it already says "Enabled," you're good.
Pre-installed on Most Setups
The External Storage Support app comes bundled with Nextcloud. You shouldn't need to download anything. If you don't see it in your app list, check the "Disabled apps" filter.
Step 2: Configure the SFTP Connection
Navigate to Administration Settings → External Storage. You'll see a form for adding new storage mounts.
Fill in the following:
Folder name: Remote Backup (or whatever you prefer)
External storage: SFTP
Authentication: RSA public key
Host: your-host.remote-backups.com
Port: 22
Root: /
Username: your SFTP username from the dashboardNow the important part: generating the SSH key pair.
Click the key icon in the authentication section. Nextcloud generates both a public and private key automatically, right there in the form. No terminal, no ssh-keygen, no manual key management. The private key stays inside Nextcloud. The public key is what you'll copy to the remote server.
After filling everything in, you'll see a red circle or X next to the storage entry. That's expected. The remote server doesn't know about your key yet.
Don't panic at the red X
A red status indicator after initial configuration is normal. The SSH key hasn't been authorized on the remote server yet. That's the next step.
See the Nextcloud documentation screenshots for the external storage configuration form layout.
Step 3: Authorize the SSH Key
Copy the public key that Nextcloud generated in the previous step. Select the entire key string from the form field. Then add it to your datastore:
Open the dashboard
Go to dashboard.remote-backups.com and log in.
Navigate to your datastore
Select the datastore you want Nextcloud to connect to.
Open the connection settings
Click Connect → rsync/borg/sftp.
Paste and save
Paste the public key into the SSH key field and click Save SSH Key.
That's it. The remote server now trusts connections from your Nextcloud instance.
See the dashboard documentation screenshots for the SSH key import modal.
Key Saved
Once saved, the key works for SFTP, rsync, and Borg connections. You don't need separate keys for each protocol.
Step 4: Verify the Connection
Go back to Nextcloud's Administration Settings → External Storage.
Click the save icon or refresh the storage entry. The status indicator should change from red to a green checkmark. This means Nextcloud successfully connected to the remote SFTP server and authenticated with the SSH key.
Green Checkmark
Connected. You're done. The SFTP storage is ready to use.
Red X
Authentication failed. Go back to the dashboard and verify the public key was saved correctly under Connect → rsync/borg/sftp.
Yellow Warning
Partial connection issue. Double-check the host, port, and username fields in the external storage form.
See the documentation screenshots for the green checkmark success state.
Browsing Remote SFTP Files in Nextcloud
Open Files in Nextcloud. You'll see a new folder with the name you chose (e.g., "Remote Backup"). Open it, and you're browsing the remote SFTP server.
Everything works like a normal folder:
- Upload files by dragging them in
- Download files by clicking them
- Share files with other Nextcloud users or via public links
- Access from Nextcloud desktop and mobile clients
The Nextcloud sync client treats external storage like any other folder. Files you move into the SFTP mount get transferred to the remote server. Files on the remote server appear in your Nextcloud interface.
SFTP Performance Tips
SFTP adds network latency to every file operation. That's the tradeoff for offsite storage. A few things to keep in mind:
Large files work well. Uploading a 500MB archive over SFTP is fine. The overhead is small relative to the transfer time.
Many small files are slower. Each file requires its own SFTP handshake. A folder with 10,000 tiny files will take much longer than a single archive of the same total size.
Best for archival workloads. Move completed projects, old photos, document archives, and media libraries to SFTP storage. Keep actively edited files on local storage.
Not ideal for databases or frequently written files. Anything that writes constantly (database files, logs, application state) should stay local. SFTP is meant for file storage, not real-time access.
Use Cases for Nextcloud SFTP Storage
Photo archive. Auto-upload phone photos to Nextcloud via the mobile app. Periodically move older albums into the SFTP folder for offsite archival. Local storage stays lean, old photos stay safe.
Document backup. Keep an offsite copy of important documents. Tax records, contracts, certificates. Store them in the SFTP mount and they're both accessible through Nextcloud and physically located in a separate datacenter.
Media overflow. Your local NAS is full, but you have 2TB of movies and music you rarely access. Move them to SFTP storage. Still browsable through Nextcloud, but not eating local disk space.
GDPR compliance. Store customer-related files or personal data in an EU datacenter with clear data residency. The SFTP datastore on remote-backups.com is hosted in Germany.
Troubleshooting Nextcloud SFTP Connections
Wrapping Up
Four steps: enable the app, configure SFTP with a generated SSH key, authorize that key in the dashboard, and verify the green checkmark. After that, remote storage works like any other Nextcloud folder.
You get offsite storage without managing remote infrastructure. Files are encrypted in transit over SFTP and stored in a GDPR-compliant EU datacenter. Nextcloud handles the connection transparently.