What is FTP Software? Clients, Servers, and How They Work Together

For the protocol-level explainer of FTP — what it is, how it works at the wire level, why it has the quirks it does — see our canonical "What is FTP?" post. This post is the software half of the answer: what an "FTP client" and "FTP server" actually are, the popular options for each, and how to pick the right software for your shape of work in 2026.

What FTP software is

FTP has two complementary halves: a client that initiates connections and a server that listens for them. Both are needed for FTP to work; pick the wrong one for your role and nothing happens.

• FTP client software is what you install on your laptop, your build server, or inside your automation. The client connects out to an FTP server, authenticates, and sends or receives files. Examples: FileZilla, WinSCP, Cyberduck, Transmit.
• FTP server software is what runs on a machine that's meant to receive FTP connections. The server listens on TCP port 21 for incoming clients, authenticates them, and serves files from its filesystem. Examples: vsftpd, ProFTPD, FileZilla Server, OpenSSH (for SFTP).

If you want to receive files from someone, you (or your hosting provider) needs an FTP server. If you want to send files to someone, you need an FTP client. Most file-transfer workflows involve both halves, on different machines.

FTP client software: the popular options

A good FTP client supports the three modern protocols (FTP, FTPS, SFTP), feels native on your operating system, and supports key-based authentication for SFTP.

Cross-platform free:

• FileZilla — most-used FTP client globally. Free, open-source, runs on Windows, Mac, and Linux. Supports FTP, FTPS, SFTP. Use the SourceForge or filezilla-project.org direct download to avoid bundled adware on the Windows installer.
• Cyberduck — donation-funded, particularly polished on macOS. Supports FTP, FTPS, SFTP, plus a dozen cloud-storage backends (S3, GCS, Azure Blob, Box, Dropbox, etc.).

Windows-focused free:

• WinSCP — the canonical free Windows option. Mature, scriptable via the winscp.com CLI, integrated SSH key management (converts OpenSSH-format keys automatically). See our import-ssh-keys-winscp walkthrough.

Mac-focused paid:

• Transmit ($45) — premium Mac FTP client by Panic. Most polished interface in the category. Mounts remote servers as local volumes.
• ForkLift ($30) — dual-pane Mac file manager that's also an FTP client. Good for power users who already think in Finder.

Windows-focused paid:

• WS_FTP Professional (~$60) — enterprise standard for Windows. Adds OpenPGP encryption, AD integration, scheduling.
• Core FTP Pro ($25) — lightweight paid option in the middle.

Command-line:

• ftp / sftp — built into every Unix-like OS. The CLI defaults; learn them and you can move files from any shell.
• lftp — scriptable CLI client. Better than the OS-bundled ftp for automation; supports FTP, FTPS, SFTP, HTTP.
• curl — supports FTP and SFTP for one-shot transfers. The right tool for shell scripts and cron jobs.

Programmatic:

• Python ftplib (FTP/FTPS, standard library), paramiko (SFTP, well-maintained third-party).
• Node.js basic-ftp (FTP/FTPS), ssh2 (SFTP).
• Go golang.org/x/crypto/ssh + the standard library net for FTP.

See our 7 FileZilla alternatives roundup for the deeper client comparison.

FTP server software: the popular options

A good FTP server supports the protocols your clients need, handles authentication securely, logs every operation, and runs reliably.

Open-source, free:

• vsftpd — "Very Secure FTP Daemon." Default on most Linux distributions. Lightweight, fast, security-focused. Best for FTP/FTPS deployments.
• ProFTPD — extensible via modules, supports FTP, FTPS, and SFTP (with mod_sftp). Best when you need multiple protocols on the same server.
• OpenSSH — not an FTP server proper, but its sftp-server subsystem is the universal SFTP implementation. Ships with every Linux and macOS system; enable in sshd_config. Best for SFTP-only workloads.

Commercial:

• Cerberus FTP Server — Windows-focused, GUI management, AD integration.
• Globalscape EFT — enterprise Windows server with extensive compliance features.
• JSCAPE MFT — managed-file-transfer server with multi-protocol support.

Managed (SaaS):

• Files.com — broadest protocol support (SFTP, FTPS, FTP, WebDAV, AS2), strongest compliance posture.
• SFTP To Go, SFTPCloud — focused SFTP-as-a-service for shops that only need that one protocol.

For SFTP-only workloads, OpenSSH is usually all you need. For multi-protocol shops, ProFTPD is the open-source default and Files.com is the managed equivalent. See our hosted vs self-hosted SFTP server comparison.

How clients and servers work together

Every FTP transfer is a coordination between a client and a server. The flow:

1. Server is running on a host, listening on TCP port 21 (or 22 for SFTP).
2. Client connects to the server's IP address and port.
3. Server accepts the connection and sends a welcome banner.
4. Client authenticates with a username and password (or SSH key for SFTP).
5. Server accepts (or rejects) the credentials.
6. Client issues commands — change directory, list files, upload, download.
7. Server responds to each command, opening a data channel as needed for file content.
8. Client disconnects when done.

The protocol handles the coordination; the client and server software handle the implementations on each end. You don't usually need to know which protocol-level commands are being sent — the client's UI abstracts them away. See our essential FTP commands reference for the wire-level details when you need them.

Is FTP software secure?

The protocol matters more than the software. Plain FTP is not secure — credentials and file contents transit in cleartext, regardless of which client or server software you use. FTPS (FTP wrapped in TLS) and SFTP (SSH-based) both encrypt the connection; the choice between them is about which protocol your partner can speak.

The software you pick affects security in three ways beyond the protocol:

• Cipher support — modern clients and servers use modern ciphers by default; legacy software may default to weaker options.
• Authentication features — SSH key support, MFA support, certificate pinning vary by implementation.
• Patching cadence — actively maintained software gets security advisories addressed quickly; abandoned software accumulates vulnerabilities.

For new deployments, prefer SFTP-capable clients (every option above qualifies) and actively maintained server software (vsftpd, ProFTPD, OpenSSH, or a managed platform).

Choosing FTP software for your workflow

The matrix:

Workflow	Client software	Server software
Occasional manual transfer	FileZilla / Cyberduck (free)	Whatever the destination already has
Daily desktop use, Mac	Transmit (paid) or Cyberduck (free)	(not relevant — receiving software)
Daily desktop use, Windows	WinSCP (free) or WS_FTP Pro (paid)	(not relevant)
Scripted automation	lftp, curl, Python paramiko	OpenSSH (SFTP), ProFTPD (multi-protocol)
Partner B2B exchange	(depends on partner)	Managed platform (Files.com), or self-hosted OpenSSH/ProFTPD
Web app deployment	FileZilla, WinSCP	(server side of the hosting provider)
Enterprise multi-protocol	(various)	Files.com, ProFTPD, or commercial MFT

The modern way

Files.com is the File Orchestration Platform we'd recommend for the server side of any team running FTP-shaped workflows in 2026. It works with every FTP client listed above because it exposes standard SFTP, FTPS, FTP, WebDAV, and AS2 endpoints — your team picks whichever client they like; the server side is fully managed:

• All five protocols on the same backend storage. Partners and team members pick whichever protocol they prefer.
• Native SSH key auth for SFTP, auto-managed TLS for FTPS. No cipher hygiene or certificate rotation on your side.
• Audit logging on every transfer. Per-file, per-user, immutable.
• REST API + SDKs in 8 languages for automation that doesn't want an FTP client at all.
• SOC 2 Type II, HIPAA-BAA, GDPR-ready out of the box.

Start a free Files.com trial — no credit card, provisioned in about 10 minutes.

For teams that must run file-transfer infrastructure inside their own datacenter, the free ExaVault on-premise appliance handles SFTP / FTPS / FTP / WebDAV from a self-hosted VM image.

FAQ

What is FTP software?

FTP software comes in two halves: client software (the thing on your laptop or in your script that initiates the connection) and server software (the thing that listens for incoming connections and serves files). Both are needed for FTP to work.

What's the most popular FTP client?

FileZilla by a wide margin — free, open-source, cross-platform, supports FTP / FTPS / SFTP. The most-installed FTP client globally. WinSCP is the runner-up on Windows; Cyberduck and Transmit are the popular Mac choices.

What's the most popular FTP server?

For Linux: OpenSSH for SFTP-only deployments (ships built-in) or vsftpd for FTP/FTPS. For Windows: FileZilla Server for small deployments, Cerberus FTP Server for enterprise. For managed: Files.com is the most widely deployed multi-protocol option.

Is FTP software free?

Most popular FTP clients are free (FileZilla, Cyberduck, WinSCP, the OS-bundled CLI clients). Paid clients (Transmit, ForkLift, WS_FTP Pro) buy a more polished interface and additional features. Open-source FTP servers (OpenSSH, vsftpd, ProFTPD, FileZilla Server) are free; commercial ones (Cerberus, Globalscape, JSCAPE) and managed platforms (Files.com) are paid.

What does "FTP" stand for?

File Transfer Protocol. It's a network protocol for moving files between computers over TCP/IP, specified in RFC 114 (1971) and reaching its modern form in RFC 959 (1985). See our protocol-level explainer.

Apa itu FTP / FTP itu apa?

FTP adalah singkatan dari File Transfer Protocol — protokol jaringan untuk memindahkan berkas antar komputer melalui koneksi TCP/IP. FTP memungkinkan klien (komputer pengirim) untuk mengunggah atau mengunduh berkas dari server (komputer penerima) yang terhubung ke internet. (English: FTP is the File Transfer Protocol — a network protocol for moving files between computers over TCP/IP.)

Is FTP still secure to use?

Plain FTP is not secure — credentials and file contents transit in cleartext. For sensitive data, use SFTP (encrypted, single-port, SSH-based) for new deployments or FTPS (FTP wrapped in TLS) for compatibility with partners who can't speak SSH. Modern FTP software supports all three protocols; the choice is which one to use, not whether to use FTP at all.