Amazon S3 is one of the world's most widely used object storage services, built for durability, scalability, and integration with the broader AWS ecosystem. It is purpose-built for programmatic access via its RESTful API, and as a result, FTP and SFTP connections require additional steps. AWS does offer its own managed SFTP service, AWS Transfer Family, which layers SFTP access on top of S3, but it comes with per-hour server fees, per-GB transfer charges, and an IAM and infrastructure configuration process that requires meaningful AWS expertise.
Couchdrop takes a different approach. It connects directly to your existing S3 bucket using an IAM key pair and acts as a fully managed SFTP and FTP/S gateway with no servers to provision, no IAM trust policies to configure, and no ongoing infrastructure to maintain. Your partners and automated systems connect to Couchdrop using standard SFTP or FTP/S clients, and Couchdrop reads and writes files directly to your S3 bucket. At no point does Couchdrop store your files in intermediate storage.
In this tutorial, you will connect your Amazon S3 bucket to Couchdrop, create a dedicated SFTP user with access to that bucket, and verify the connection using FileZilla. By the end, your trading partners or internal systems will be able to transfer files directly into or out of your S3 bucket using any standard SFTP client.
Prerequisites
To complete this tutorial, you will need:
- A Couchdrop account with Admin permissions. You can sign up for a free trial at couchdrop.io.
- An Amazon S3 bucket already created in your AWS account. Follow AWS's guide to creating an S3 bucket if you have not done this yet.
- An AWS IAM access key and secret with sufficient permissions to read and write to the target S3 bucket. Follow AWS's guide to managing IAM access keys if needed.
- The AWS region your S3 bucket is located in (for example,
us-east-1). - FileZilla installed on your local machine for testing. Download it from filezilla-project.org.
Step 1 — Connecting Your S3 Bucket to Couchdrop
In this step, you will add your Amazon S3 bucket as a storage connection in Couchdrop. Once connected, Couchdrop treats your S3 bucket as a folder that SFTP users can be granted access to.
Log in to Couchdrop at my.couchdrop.io. From the dashboard, click + Create and select Connect to Storage, or navigate to the Connections tab and click + Add Connection.
From the list of available connections, select Amazon S3.
Give a name to identify the integration and a name for the folder that will represent your S3 bucket in Couchdrop's virtual file browser.
You will be prompted to enter the following fields:
- S3 Access Key: Enter your AWS IAM access key ID. This is the identifier half of your IAM credentials. Couchdrop uses this to authenticate with AWS on your behalf.
- S3 Access Key Secret: Enter your AWS IAM secret access key. This is the confidential half of your IAM credentials. Store this value securely — treat it like a password.
- S3 Bucket (Optional): Specify a particular bucket to connect to.
- S3 Region: Enter the AWS region where your S3 bucket resides, for example
us-east-1orap-southeast-2. Using the correct region ensures requests are routed to the right AWS endpoint.
Once you have entered these values, click Save and Test. Couchdrop will attempt to authenticate with AWS using the credentials you provided. If the test succeeds, you can then use the Choose a folder option if you wish. This allows you to select the specific bucket or subfolder path within S3 that SFTP users should access. Selecting a subfolder rather than the bucket root is good practice when you want to restrict what partners can see and write to.
Click Add Integration > to complete the connection.
You have now connected your S3 bucket to Couchdrop. In the next step, you will create an SFTP user who can connect to this storage.
Step 2 — Creating an SFTP User
With your S3 bucket connected, you will now create a dedicated SFTP user account. SFTP users in Couchdrop are separate from administrator accounts and are scoped to a specific folder location within your connected storage. Typically, these will be for external users like partners, vendors, or clients. Specifying a folder prevents partners or automated systems from accessing anything beyond the directory you designate.
From the Couchdrop dashboard, click + Create or go to SFTP & FTPs on the sidebar and then click + Create New. Select SFTP User.
Configure the following fields:
- Username: Enter a unique username for this user, for example
s3_partner_upload. This is the username your partner or system will use when connecting via SFTP or FTP/S. - Home/Root Directory: Click Select a location and navigate to the S3 connection you created in Step 1. Select the folder within your S3 bucket that this user should access. Users cannot navigate above this directory — it is their root.
- Password: Choose Autogenerated Password to have Couchdrop generate a secure password, or select Custom Password to enter your own. If you select autogenerated, you must download and save the credentials immediately after creation — Couchdrop does not store passwords after this screen.
- Public and Automatic RSA Key creation. Couchdrop supports public key-based authentication with SFTP and SFTP. Checking this option will create a private and public key pair to use with Couchdrop.
Click Create user.
After creation, Couchdrop will display the connection credentials, including the username, password, and SFTP endpoint in the format sftp://<^>username<^>@<^>your_company<^>.couchdrop.io. Use the Download Credentials button to save these details, then share them securely with the person or system that will be connecting.
You have created a dedicated SFTP user scoped to your S3 bucket. In the next step, you will verify the connection using FileZilla.
Step 3 — Testing the Connection with FileZilla
Before sharing credentials with a partner or configuring an automated system, verify that the SFTP connection works and that files land in your S3 bucket as expected.
Open FileZilla and navigate to File > Site Manager, or use the shortcut Ctrl+S (Windows/Linux) or Cmd+S (Mac).
Click New Site and configure the following fields:
- Protocol: Select SFTP – SSH File Transfer Protocol from the dropdown.
- Host: Enter your Couchdrop SFTP endpoint hostname, for example
<^>your_company<^>.couchdrop.io. - Port: Leave this as
22, which is the default SFTP port. - Logon Type: Select Normal.
- User: Enter the username you created in Step 2.
- Password: Enter the password from the credentials you downloaded.
Click Connect. If this is your first time connecting to this host, FileZilla may prompt you to accept the server's host key fingerprint. Review it and click OK to proceed.
Once connected, the right pane in FileZilla will show the contents of the S3 folder you assigned as the user's root directory. Upload a test file by dragging it from the left (local) pane to the right (remote) pane.
After the upload completes, log in to the AWS S3 console and navigate to your bucket. Confirm that the test file appears at the correct path. If it does, your SFTP-to-S3 connection is working correctly.
Next Steps
In this tutorial, you connected your Amazon S3 bucket to Couchdrop using an IAM key pair, created a dedicated SFTP user scoped to a specific S3 folder, and verified the connection using FileZilla.
Your partners and automated systems can now transfer files directly into or out of your S3 bucket using any standard SFTP client without any AWS-specific knowledge, SDK integrations, or infrastructure management on their part.
From here, you might want to explore:
- Transfer Automations to automatically move, rename, or route files once they arrive in S3.
- Upload Links to give partners a secure web portal for uploading files directly to S3 without needing an SFTP client at all.
- Shared Links to send files from your S3 bucket to partners via a secure, expiring download link.
For more information on the Amazon S3 connector and supported transfer methods, see the Amazon S3 integration page.