BackendsideFTP
User Guide — Version 3.2.0
BackendsideFTP is a free file transfer client for Windows that speaks FTP, FTPS (explicit and implicit TLS) and SFTP. Open several servers at once in tabs, move files by drag-and-drop in either direction, and follow every upload and download in one shared transfer queue.
Contents
1. Connecting to a server
Quick Connect
The Quick Connect bar at the top is the fastest way in. Pick a protocol, type the host and, if needed, a port, user name and password, then click Connect. Only the host is required, so anonymous FTP works. The port fills itself in from the protocol (21 for FTP and explicit FTPS, 990 for implicit FTPS, 22 for SFTP); leave it at 0 for the default, or type your own.
The password stays in the field after connecting, so you can open another session straight away. If you connect to a server that already has an open tab, BackendsideFTP asks before opening a duplicate.
New connection dialog
Click + New or press Ctrl+N for the full dialog, which adds a display name, a default remote folder, passive/active mode and SSH key login.
Logging in with an SSH key
For SFTP, fill in Private key (SFTP) — Browse… opens your .ssh folder — and, if the key is protected, its Key passphrase. You can use a key, a password, or both. Servers that only allow keyboard-interactive login accept the password too.
2. Site Manager
Open Sites… (Ctrl+M) to save servers you use often. Click New, fill in the host, protocol, port, user name, password or private key, an optional Default remote folder and passive/active mode, then Save. Select a site and click Connect to open it.
- The session opens in the site’s Default remote folder. If that folder can’t be listed, it falls back to your login folder and says so in the status line and the log.
- A site’s passive/active setting overrides the Quick Connect default in Settings.
- Passwords and key passphrases are encrypted with your Windows account — never written to disk in plain text.
3. Host keys & certificates
The first time you connect to an SFTP server, BackendsideFTP shows its SSH host-key fingerprint; for FTPS it shows the server’s TLS certificate. You choose:
| Button | What it does |
|---|---|
| Reject (default, Esc) | Don’t connect. |
| Trust once | Trust it for the rest of this session tab — including every transfer and reconnect it starts. You are asked again next time. |
| Trust always | Remember it permanently. |
4. Browsing & managing files
Each session shows your local files on one side and the remote server on the other. Double-click a folder to open it, use ↑ to go up a level and ⟳ to refresh. The breadcrumb bar shows where you are; the local pane’s quick-locations dropdown jumps to Desktop, Documents, Downloads or any drive.
Right-click in either pane for Open / Enter, Upload or Download, New folder…, Rename…, Delete and Refresh; the local pane adds Open in Explorer.
- Deleting a remote folder removes it and everything inside it, after a confirmation. Symbolic links are removed as links — the files they point to are never touched.
- Permissions… on a remote item opens the CHMOD editor: Read / Write / Exec checkboxes for Owner, Group and Public, with the octal mode (e.g.
644) shown as you click. - Problems are shown where they happen: a folder you aren’t allowed to open says so, and an unsafe remote name appears as an error in the pane rather than interrupting you.
When a session is disconnected, the remote pane is dimmed with “Not connected — click Connect to reconnect.” A connection that drops on its own reconnects automatically and returns to the folder you were in.
5. Uploading & downloading
- Drag and drop files or folders from the local pane to the remote pane to upload, or the other way to download. Multi-select works, and folders transfer with everything inside them.
- Or select items and click ⬆ Upload (Ctrl+U) or ⬇ Download selected.
Folder downloads and links
A symbolic link to a file downloads like a normal file. Links to folders are not followed (that is what stops endless loops). Anything left out — a linked folder, a subfolder you can’t read, a file with an unsafe name — is listed in the folder row’s ⚠ tooltip and in the log, so nothing goes missing silently. On upload, Windows junctions and links inside the folder are skipped.
When the file already exists
What happens is set in Settings → Transfers → If target exists: Overwrite replaces it, Skip leaves it, Rename saves the new one as name (1).ext, and Fail marks the transfer failed.
6. The transfer queue
Every upload and download from every tab goes into one shared queue at the bottom. Folders appear as expandable rows with their files underneath, and show combined size, progress and speed.
| Button | What it does |
|---|---|
| Pause / Resume | Pause a transfer and continue later from where it stopped. On a folder row, applies to every file in it. |
| Cancel | Stop the transfer. A cancelled download’s partial file is removed. |
| Retry | Run a failed or cancelled transfer again. |
| Retry all | Re-run every failed transfer in the queue, including failed files inside folders. |
| Remove | Take a job off the list — stopping it first if it hasn’t finished. |
| Speed limit… | Cap the selected transfer (or every file in a selected folder) in KB/s; 0 removes the cap. Takes effect immediately and is shown as a 🐢 badge. The app-wide limit still applies — the tighter of the two wins. |
| Clear completed | Remove finished rows. |
| Clear all | Cancel everything and empty the queue. |
A failed transfer shows a ⚠ in its status column — hover it for the reason. Failed transfers are retried automatically first (see Retries on error in Settings).
7. Session log & history
Each session tab has a collapsible Log panel (toggle it from the session header). For FTP and FTPS it shows every command and server reply; for SFTP, one line per operation — connect, list, upload, download, rename, delete, permissions — plus disconnects and reconnects. Copy and Clear sit beside it, and it keeps the newest 1,000 lines. Passwords and user names are never logged.
History shows your recent completed transfers, kept across launches; Clear history empties it.
8. Settings
Open with the ⚙ button.
| Setting | What it does |
|---|---|
| Speed limit (KB/s) | App-wide bandwidth cap for all transfers. 0 = unlimited. |
| If target exists | Overwrite (default), Skip, Rename or Fail — see section 5. |
| Retries on error | How many times a failed transfer is retried automatically, 0–10 (default 2). |
| Quick Connect mode | Passive mode (recommended for most networks and behind NAT) or, unchecked, Active. Saved sites can override it. |
| Keep-alive (seconds) | Sends a small keep-alive so idle sessions aren’t dropped by the server. 0 = off. |
| Log verbosity | Verbose records the full protocol transcript for every connection and transfer in the log files. Open log folder takes you there. |
9. Shortcuts, tray & themes
| Shortcut | Action |
|---|---|
| Ctrl+N | New connection |
| Ctrl+M | Site Manager |
| Ctrl+U | Upload the local selection |
| Ctrl+W | Close the active session tab |
- Dialog buttons have Alt+letter shortcuts (the underlined letter), and every button is labelled for screen readers.
- 🌓 switches between light and dark themes; your choice, window size, position and pane layout are remembered.
- BackendsideFTP can minimise to the system tray — double-click the tray icon to restore it. Launching it again while it is running simply brings the open window forward.
10. Tips & FAQ
The connection fails or the listing hangs on FTP
Try toggling Passive mode — passive works for most home and office networks; some older servers need active. The session’s Log panel shows exactly where it stopped.
My SFTP server says “Login failed”
Check whether the server expects a key rather than a password, and add it under Private key (SFTP). An SFTP connection needs either a password or a private key.
I’m asked to trust the server every time
Trust once lasts for that session tab. Choose Trust always if you recognise the fingerprint and want it remembered.
A folder download finished but some files are missing
Hover the ⚠ on the folder row: it lists what was skipped and why — typically links to other folders or subfolders you don’t have permission to read.
Is SCP supported?
No — use SFTP, which covers the same need and is what most SSH servers offer.
Where is my data stored?
Saved sites, trusted keys and certificates, settings and logs live in %LOCALAPPDATA%\BackendSideFTP\. Uninstalling does not delete them; remove that folder yourself for a clean slate.