What is SFTP?

SFTP is one of several standard protocols used for transferring files, but it differs significantly from FTP, FTPS, and TFTP in terms of security and use cases.

FTP Secure (FTPS) adds TLS/SSL encryption on top of the original File Transfer Protocol (FTP) to protect data in transit and uses SSL certificates for authentication. However, both FTP and FTPS are increasingly treated as legacy options in modern environments because they are harder to configure securely (multiple ports, certificate management, firewall issues) compared to newer alternatives.

SFTP, by contrast, was designed from the ground up as a secure file transfer protocol. It runs over SSH, provides encryption and authentication in a single channel, avoids complex certificate management, and has broad support across modern operating systems and cloud platforms. As a result, SFTP is now far more widely used than FTPS.

Trivial File Transfer Protocol (TFTP) is a minimal, lightweight protocol based on a simple client–server model. It has no built-in authentication or encryption, so it must be wrapped in other security measures to be used safely.

SFTP, on the other hand, includes strong security by default. While SFTP supports a wide range of enterprise use cases, TFTP is generally limited to tightly controlled local networks, most commonly for booting or updating hardware, firmware, or operating systems.

In practice, SFTP has become the default choice for secure file transfer:
FTP is insecure, FTPS is complex and largely legacy, and TFTP is only suitable for very narrow, internal use cases, whereas SFTP offers strong security, simpler operations, and broad support.

SFTP works by transferring files through a secure, encrypted connection created by the SSH (Secure Shell) protocol. Instead of sending data in plain text like traditional FTP, SFTP wraps all communication inside a protected tunnel, ensuring that file names, contents, and credentials cannot be intercepted.

The process happens in several simple steps:

1. Connect to the server over TCP on port 22.
2. SSH negotiates encryption and sets up a secure tunnel.
3. Server and client authenticate each other.
4. Client switches to the SFTP subsystem.
5. You perform file operations (upload, download, list, delete) as SFTP commands inside the encrypted tunnel.
6. You disconnect; the tunnel closes.

To use SFTP, you need:

• An SFTP/SSH server: its address (hostname or IP) and usually port 22.
• A user account on that server.
• Credentials: password, or SSH key pair (private key on your machine, public key installed on the server).

Optional but ideal:

• Keys instead of passwords.
• Two-factor authentication is supported.

SFTP is important because it provides a secure and reliable way to transfer files across untrusted networks, making it ideal for sensitive data. It encrypts both credentials and file contents, ensures data integrity during transfer, and supports compliance requirements through detailed logging. 

SFTP is also easier to deploy than traditional FTP because it uses a single port, and it offers rich features and automation capabilities for backups, integrations, and routine file-transfer workflows.

Like any technology, it offers benefits and trade-offs depending on how it's implemented and managed.

1. Secure data transfer
   SFTP encrypts both credentials and file contents, protecting data from eavesdropping, tampering, or interception. SSH-based host authentication ensures you're connecting to the correct server.
2. Reliable and efficient for large files
   SFTP handles large, bulky file transfers well, with built-in support for resuming interrupted transfers and handling unstable network conditions.
3. Broad accessibility and flexibility
   SFTP supports user-to-server and server-to-server transfers, making it versatile for integrations, automated workflows, and cross-system data exchange.
4. Firewall-friendly and simple to deploy
   Operating over a single port (typically 22), SFTP avoids the complex port ranges required by traditional FTP, reducing configuration effort and deployment risk.

1. More complex setup and management
   Because SFTP includes authentication, encryption keys, and strict permissions, it can be harder to configure and maintain, especially in large or highly regulated environments.
2. Security depends on proper configuration
   While SFTP itself is secure, poor key management, weak passwords, outdated SSH versions, or misconfigured permissions can expose systems to attacks. The protocol is safe, but its security relies on correct administration.
3. Not ideal for very lightweight or embedded environments
   SFTP is heavier than simple protocols like TFTP and may be unnecessary for small, closed-network use cases such as booting devices or transferring firmware.

SFTP is used whenever organizations need to move files securely, reliably, and with controlled access, especially when data is sensitive or large. Here are some examples:

General file transfer & automation

• Uploading website files, moving reports or backups between systems, sending large datasets to cloud storage, and automating file transfers in DevOps pipelines.

Business data exchange

• Sharing CSV/XML feeds between partners, sending sales or inventory data, and transferring large design files or project assets securely.

Finance, payroll & billing

• Moving payroll files to central systems and exchanging confidential customer or transaction data between banks, processors, and regulators.

Healthcare & regulated industries

• Transferring health records, lab results, and imaging files, or sharing sensitive datasets while meeting HIPAA/GDPR requirements.

Integrations, backups & migrations

• Running scheduled batch integrations, automating off-site backups, and performing large data migrations between legacy and new systems.

Content distribution & internal collaboration

• Delivering software builds, firmware updates, reports, or documents, and securely syncing files between headquarters and remote offices.