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Set Up SFTP Using SSH Key Authentication

If your organization restricts password-based authentication (common in AWS-managed or security-hardened environments), you can connect Amplify to your SFTP server using SSH key authentication instead. This guide explains how to configure a secure SFTP connection using an SSH private key and highlights important considerations when using SFTP automations.

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Why Use SSH Key Authentication?

Many enterprise and cloud environments disable password-based authentication for enhanced security. SSH key authentication provides:
  • Stronger security
  • Passwordless authentication
  • Compliance with stricter IT and security policies
  • Reduced risk of credential-based attacks

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Configure Your SFTP Connection

  1. Open SFTP Settings in Amplify.
  2. Enter your SFTP server details:
    • Host
    • Port
    • Username
  3. Under Authentication, provide your SSH Private Key.
  4. Click Save Connection.
Your SSH private key is securely used to authenticate your connection with the SFTP server. Ensure you upload the correct private key associated with the public key configured on your server.

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SSH Key Requirements

Your SSH private key must be:
  • Valid
  • Properly formatted
  • Non-empty
If the SSH key is missing, empty, or invalid, Amplify will not save the connection and you’ll receive a validation error.

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Using Both Password and SSH Key

Amplify supports configuring both:
  • Username and password
  • SSH private key
However, if your SFTP server is configured to reject password authentication (as is common in AWS-managed environments), only the SSH key will be used for authentication.
If your administrator has disabled password authentication on the server, you do not need to provide a password.

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Send Faxes via SFTP

Once the connection is successfully established:
  • Faxes can be uploaded or moved into your configured SFTP folders.
  • Amplify automatically syncs supported files to your SFTP server.
  • You can organize workflows using folders and nested subfolders.

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Update Your Authentication Method

If you’re switching from password authentication to SSH key authentication:
If a sync is currently in progress, Amplify may prevent authentication changes until the active transfer completes. This helps avoid interrupted or incomplete file transfers.
After the sync finishes, update your authentication settings and save the connection again.

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Disconnect or Remove an SFTP Connection

Before removing an SFTP connection:
  1. Disconnect the active connection.
  2. Remove the saved configuration.
Attempting to remove an active SFTP connection will display a warning and the removal will be blocked until the connection is disconnected.

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Automation Permissions

SFTP automations are managed at the account owner level.
Automations work only for the owner account. They do not execute using sub-user credentials.
If sub-users need access to files synchronized through integrations, the account owner must grant access to the corresponding destination. For example:
  • If files are synced to Google Drive, the owner must share the appropriate Google Drive folder with the required sub-users.
  • If files are synced through SFTP, the owner must ensure that sub-users have access to the appropriate folders on the SFTP server.

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Avoid Automation Conflicts

Multiple users should not configure automations that perform the same action on the same fax. For example, if both the account owner and a sub-user configure a Move to Folder automation for the same fax, the sub-user’s automation can override the owner’s automation. This may prevent the expected action from completing and make it appear that the automation has failed.
To avoid conflicts and ensure consistent behavior, manage all automations that move or synchronize files to external storage (such as SFTP or Google Drive) exclusively from the owner account.

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Troubleshooting

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Cannot save the SFTP connection

Possible causes:
  • The SSH private key is missing.
  • The SSH private key is invalid.
  • The key is incorrectly formatted.

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Authentication failed

Verify that:
  • Your SFTP server accepts SSH key authentication.
  • The corresponding public key has been added to the server for the configured user.
  • The username matches the registered SSH key.

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Unable to switch authentication methods

Wait until any active synchronization completes before updating the authentication method.

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Best Practices

For the most reliable experience:
  • Use SSH key authentication whenever supported.
  • Verify that the correct public key is installed on your SFTP server.
  • Manage SFTP automations only from the owner account.
  • Avoid configuring duplicate automations across multiple users.
  • Ensure sub-users have the required access to destination folders if they need to view synced files.