Amazon S3 vs. SFTP: Here's Why You Need Both

This is, in all honesty, a weird comparison because S3 is an object storage service and SFTP is a transfer protocol. You won't be choosing one or the other. Most real systems use both: SFTP (or FTPS/HTTPS) to exchange files, and object storage to keep them.

Let's say you want to prepare yourself a sandwich that is easy to make, affordable, provides nutritional benefits and, most importantly, delicious. Which sandwich will you make? Some people might choose a peanut butter sandwich, while others are more into jam.

We will be having both.

Indeed, we've put together a list comparing SFTP and Amazon S3, because a lot of folk are not yet sure what SFTP is, what S3 is, how they differ, or why you should really be having them together.

What is Amazon S3?

Amazon S3 (Simple Storage Service) is a cloud object storage service from Amazon Web Services (AWS). Think of it as a highly scalable place to keep files and data, not a way to “send” them.

It’s designed for:

• High durability and availability for stored data.
• Large-scale storage without managing disks or capacity planning the old-fashioned way.
• Features like versioning, encryption, lifecycle rules, and access controls, depending on how you configure it.

People use S3 for things like backups, archives, application assets, analytics datasets, customer exports, and anywhere files need to be stored reliably and accessed programmatically.

What is SFTP?

SFTP (Secure File Transfer Protocol) is a secure way to transfer files between systems. It runs over SSH (Secure Shell), which provides the encrypted channel.

People use SFTP for:

• Vendor and partner file exchanges.
• Scheduled batch jobs and recurring exports.
• Secure file sharing when a simple “drop a file here” workflow fits the business process.
• Integrations where you want a standard transfer method that works across many tools.

To better understand the security benefits of SFTP, read about SFTP Compliance and for a protocol comparison, read SFTP vs. FTPS.

SFTP vs. S3 for business continuity

Business continuity is about keeping data available through outages and being able to recover fast from human error.

Amazon S3 is built for resilience as a storage layer. It stores data redundantly across multiple multiple Availability Zones in a region, and it supports features like versioning so you can recover from accidental overwrites and deletes. That combination is why S3 is commonly used for backups, archives, and disaster recovery designs.

SFTP is not a storage system. It is a secure transfer protocol. On its own it does not provide high availability, replication, backups, or durability guarantees. Business continuity for SFTP depends on what’s behind it: the storage you land files into, how you replicate it, how you back it up, and how you validate and re-run transfers.

If you want the clean takeaway:

• S3 is the continuity-friendly place to keep files.
• SFTP is a continuity-friendly way to move files, when paired with the right storage and retry/verification behavior.

Amazon S3 vs. SFTP for scalability

Amazon S3 is designed for growth. You can keep adding data without planning disk upgrades or worrying about “where will we put the next batch of files.” In practice, you expand by storing more, not by rebuilding infrastructure.

SFTP is different because it’s a transfer method, not a storage system. SFTP can move 10 files or 10 million files, but it only works as well as the storage behind the SFTP server. If that server has limited disk space, limited throughput, or a limited number of concurrent connections it can handle, your SFTP workflow hits those limits too.

What this looks like in real life:

• With S3, scaling usually means storing more data and organizing it well.
• With SFTP, scaling often means managing the server: adding storage, improving throughput, and supporting more simultaneous users.
• With a managed SFTP service, much of that scaling work is handled for you, but the core point stays the same: S3 is storage that scales natively, SFTP is a transfer layer that depends on what it connects to.

SFTP vs. S3 for security

Amazon S3 and SFTP operate at different layers of the data journey, so their security models solve different problems rather than competing with each other.

Amazon S3 focuses on protecting data at rest. Objects can be encrypted using server-side or client-side encryption, access is governed through policy-based controls, and activity can be logged for traceability. Those capabilities matter for governance because they help teams enforce least-privilege access, monitor usage, and retain evidence showing how stored data was handled over time.

SFTP focuses on protecting data in transit. It runs inside an SSH session, which encrypts authentication and file data between client and server while also supporting key-based identity, credential controls, and host verification. In practice, that makes SFTP a transport security layer that ensures files cannot be intercepted or altered while moving between systems. Read about SFTP Security.

When compliance teams evaluate a workflow for security and controls, they usually don’t ask whether storage or transfer is secure. They ask whether both stages are secured and auditable.

Storage platforms like S3 help satisfy regulatory (HIPAA, GLBA, GDPR, SOC 2, FERPA, etc.) requirements tied to retention, access governance, and audit trails, while transfer protocols like SFTP help demonstrate that sensitive data was protected during transmission.

Systems that combine the two are often easier to validate because they provide coverage across the full lifecycle of a file, from upload to storage to retrieval.

Amazon S3 vs. SFTP for automation

Amazon S3 is built for automation. You can upload, download, and manage objects through APIs and CLI tools, and you can trigger follow-up actions when something changes. In practice, that usually means event notifications (for example, “a file was uploaded”) routed to services that can run workflows.

SFTP automates differently. It works well with scripts, CLIs, and libraries, and it’s easy to plug into batch jobs and partner transfers. But the protocol itself doesn’t include “file uploaded” notifications. If you need that behavior, you add it at the server or storage layer (for example, by polling, watching a landing folder, or using an MFT layer that sends event triggers, like SFTP To Go).

SFTP vs. Amazon S3 for portability

SFTP is portable. You can run an SFTP server on many operating systems and environments: on-prem servers, VMs, containers, or cloud instances. Wherever you can run SSH, you can usually run SFTP.

Amazon S3 isn’t something you “install.” It’s an AWS-managed storage service. You use it by creating buckets in AWS and accessing them over AWS APIs (typically via HTTPS). If you want S3-like storage outside AWS, you’d be talking about an S3-compatible service, not Amazon S3 itself.

So, what's the conclusion?

Just as the timeless pairing of peanut butter and jelly brings together two distinct flavors to create a delightful culinary experience, combining the strengths of SFTP and Amazon S3 results in a harmonious and robust secure transfer and storage solution: SFTP To Go.

With SFTP To Go you get SFTP as well as all the benefits S3 has to offer:

• Built-in high availability for stored files, plus recovery options like versioning to undo overwrites and deletes
• Security across transfer and storage, including encryption in transit via SFTP and encryption at rest on the S3 storage layer, with access controls and logs
• Modern automation for file movement and follow-up workflows, using APIs, webhooks, and event-style triggers at the storage layer
• Flexibility and scalability, using a standard SFTP interface while landing files into storage that scales without disk planning and maintenance

Combine all of the above with SFTP’s familiar interface that simply works!

By integrating the familiarity and dependability of SFTP with the advanced features and scalability of Amazon S3, SFTP To Go offers the best of both worlds, ensuring that your data is secure, accessible, and well-managed in transit and at rest.

Why settle for one when you can have the complementary benefits of both?

Frequently Asked Questions