Observer FTP

Free FTP, SFTP and SSH client for Windows

Know what's changed before you upload.

Observer FTP puts your PC and your server side by side and checks every file. It shows what needs uploading, what needs downloading, and which files only look different. When you need the command line, an SSH terminal opens in the next tab.

Download for Windows Free while in testing · Windows 10 and 11
yoursite.co.uk

A website folder after two edits. Switch to Size check to see what an FTP app that compares sizes would flag, and what it would miss.

For AI agents and scripts

Let your AI assistant do the uploading.

AI coding assistants like Claude Code, Cursor and Copilot can use Observer FTP to see what's changed on your site and upload just those files when they've finished editing. Build scripts can too. It all runs through observer-ftp, a small command-line companion that uses the sites you've already saved.

They never see your passwords, and files like .env stay on your PC. Automation stays off until you switch it on for a site, nothing moves without an explicit go-ahead, and every upload lands in History where you can undo it.

Built-in SSH terminal

Your server's command line, in the next tab.

Open an SSH terminal on any site in one click, already in the folder you were browsing. It signs in with the login you've saved and the server key you've approved, and full-screen tools like nano and top work as they should.

Keep servers you only SSH into in their own list, apart from your file sites.

yoursite › httpdocs
/ › httpdocs
Not on this PC
+
partials/
There's no partials folder on this PC yet.Create it here Download it

Link two folders. Browse them together.

Open the matching folder on each side and press Link folders. Open a folder on one side and the other follows. The site remembers the pair, so next time it opens where you left off.

If a folder only exists on one side, create it, or copy the whole thing across in one go.

Upload what you changed. Nothing else.

Upload changes checks the folder you're in and every folder inside it, then lists the files you've edited since your last upload, grouped by folder, each with a tick box. It even catches an edit that keeps a file the same size, like a version number going from 1.9 to 2.0.

Files that should never reach the server, like .env and .git, are left out. Each site has its own leave-out list.

Upload changes
  • This folder
  • config.phpchanged
  • index.phpchanged
  • offers.phpnew
  • css/
  • site.csschanged

Left out: .env, .git, node_modules

Upload 4 files
05/11 09:44Uploaded index.php and offers.php1 server copy kept, 1 newUndo
04/11 16:20Uploaded header.phpServer copy keptUndo
01/11 10:05Downloaded 12 filesLocal copies kept (3)Undo

Every upload can be undone.

Before Observer FTP replaces a file on your server, it keeps the copy that was there. History lists each upload with what it replaced, and Undo puts it all back.

No more saving header-old.php on the server just in case.

See the lines, not just the file.

Open any pair side by side to see exactly which lines differ, with line endings ignored. Then upload your copy or download the server's from the same window.

This PC
41$title = 'Offers';
42$limit = 12;
43include 'header.php';
44
Server
41$title = 'Offers';
42$limit = 6;
43include 'header.php';
44

Most size differences aren't real.

Windows ends each line of a text file with two characters. Linux servers use one. Upload in text mode and every file arrives a few bytes smaller, so an FTP app that compares sizes flags files you never touched.

Observer FTP counts the line endings and tells you when the contents match. It also uploads byte for byte, so it never causes the mismatch in the first place.

functions.phpSame contents
This PCServer
Size18,442 bytes17,903 bytes
Lines539539
Line endingsCRLF (Windows)LF (Unix)
Difference539 bytes, one per line. Nothing to upload.

The rest of the toolkit

Everything you use an FTP app for every day, in a window that looks like it belongs on Windows 11.

Connection tabs

Keep several sites open at once, each in its own tab.

Filter both sides

Type once and both lists narrow down together.

Quick jump

Press Ctrl K and type part of a site or folder name.

Edit on the server

Open a remote file in your own editor. Each save uploads it.

FTP, FTPS, SFTP and SSH

Files over FTP, FTPS or SFTP, a terminal over SSH, and a warning if a server's identity ever changes.

Your FileZilla sites

Import your Site Manager, folders and saved passwords included.

Move to a new PC

One file, locked with a password you choose, carries every site across.

Transferred dates

Sort by when files were last copied, while they keep their real dates.

Dark and light

Follows Windows, or pick one yourself.

Your passwords stay on your PC.

Saved passwords go into Windows Credential Manager, the encrypted store Windows uses for its own sign-ins. They're never written to a plain file, and they never leave your PC unless you move them to a new one yourself.

No accountDownload it and use it. There's nothing to sign up for.
No tracking in the appIt connects only to the servers you add. Nothing about you or your files is sent anywhere else.
Cookie-free websiteThis site counts visits with Cloudflare Web Analytics, which uses no cookies and doesn't follow you around the web. Privacy policy

Download Observer FTP

Free while it's in testing.

Download for Windows

Version 0.1 · Windows 10 (version 2004 or later) and Windows 11 · 64-bit · 61 MB

Because the app is new, Windows may say it protected your PC the first time you open it. Choose More info, then Run anyway.

Questions

Is it really free?

Yes. Observer FTP is free to download and use while it's being tested.

Can I bring my sites over from FileZilla?

Yes. Import from FileZilla reads your Site Manager, including folders and saved passwords. Passwords locked by FileZilla's master password can't be read, so you type those in once.

Which servers does it work with?

Any server that offers FTP, FTPS (explicit or implicit) or SFTP for files, and SSH for the terminal, signing in with a password or a key file.

Will it change my files?

Only when you upload, download, rename or delete. Files are copied byte for byte and never converted, and History can undo every upload and download.

Is automation safe to switch on?

It's off for every site until you turn it on, and you can turn it on for just one. Commands only preview until they're given --yes, files changed on both sides are left alone, files on the site's leave-out list like .env are never uploaded, and every transfer can be undone from History.

How do I move it to a new computer?

Choose Move to a new PC and save one file, locked with a password you pick. Open it in Observer FTP on the new PC and every site, password and folder pair is there.