Frequently Asked Questions

What is S3Client?

S3Client is an application you install on your computer to transfer and manage files in S3 storage. Its interface lets you browse files and folders, upload files to that storage, download them to your computer, or delete them.

Amazon S3 is a storage service from Amazon: it keeps your files on servers that you access over a network. Other storage services use the same communication rules and are described as “S3-compatible.” S3Client can connect to Amazon S3 and to these services.

For example, you can use S3Client to upload photos or documents from your computer and download them when you need them. You need access to your chosen storage service: that service stores your files, while S3Client is the application you use to manage them.

S3Client also supports professional file transfers and storage management. Developers building applications that use S3 can use it occasionally to inspect their application’s files, transfer data, or check file properties.

What is an S3-compatible storage service?

Amazon S3 is an object storage service from Amazon. Files are stored as objects, grouped in storage containers called buckets. Applications communicate with the service through its API, an interface that defines requests for actions such as listing, uploading, downloading, or deleting objects.

A service is described as “S3-compatible” when it implements this API so that applications designed for Amazon S3 can communicate with it. This lets you use S3Client with another storage service by entering its connection address, called an endpoint, and the access credentials it provides. Your files are stored on that service.

S3 compatibility does not guarantee support for the entire Amazon S3 API. Common operations are available, but some features, such as object versioning or protection against deletion, may vary between services.

Is S3Client free?

Yes. The current version of S3Client is free for personal use and for a company’s internal needs. You do not need to purchase a license or enter a license key. Use of the software is subject to the EULA.

The software is free. Your chosen storage service may charge you for file storage, data transfers, and certain operations, depending on its pricing. These charges are separate from S3Client.

Paid versions, features, or plans may be offered in the future. Future versions are not guaranteed to remain free.

How does S3Client adapt to different storage providers?

Amazon S3 and S3-compatible services use the same communication rules for common operations, such as browsing, uploading, and downloading files. S3Client can therefore communicate with multiple providers and lets you use them through the same interface.

This does not mean that all these services offer exactly the same features. For example, some let you keep previous versions of a file or protect it from deletion for a set period, while others do not offer those features.

To account for these differences, each account in S3Client has capabilities: settings that specify which features the service supports. S3Client uses them to adapt the commands and options it offers. The provider preset selected when you create the account supplies the initial values, which you can then adjust to match your service. S3Client does not detect these capabilities automatically.

Checking a capability in S3Client is not enough to make a feature usable: the service must support it, and your credentials must grant the necessary permissions. This setting does not enable the feature on the service. These settings are in the account’s Capabilities tab. See Configuring account capabilities to learn how to adjust them.

What do I need to connect my account?

You need access to Amazon S3 or an S3-compatible service. Adding an account in S3Client does not create an account with the provider.

To configure the connection, have the following ready:

• Credentials for the service: usually an Access Key ID and a Secret Access Key, plus a Session Token for temporary credentials. You can also use AWS profile or AWS default credential chain to load credentials from an existing source.
• The service address and region: your provider supplies the connection address, called the Endpoint, and the region to use. The preset you select in S3Client may already fill in these values.
• The required permissions: your credentials must allow the actions you want to perform, such as reading, uploading, or deleting files.

S3 access keys are separate from the username and password you use to sign in to the provider’s website. See creating an account to enter these details and test the connection.

Do my files pass through S3Client’s servers?

No. Your files are not relayed through servers operated by Almageste, the developer of S3Client. Uploads and downloads transfer data between your computer and the storage service you choose, following your network settings, including any configured proxy.

When copying between S3 locations, the data may be copied on the service or pass through your computer, depending on which type of copy is possible.

Almageste does not collect your files or S3 credentials through the software. Your storage service applies its own privacy policy. See S3Client’s privacy policy for details.

Are my credentials protected?

Secret keys and session tokens entered in S3Client are stored on your computer. Their protection depends on your settings:

• Without a master password, they are encrypted with a key built into the software. This prevents direct reading, but does not protect against someone who has access to the application and its data.
• With a master password, they are protected by your password and must be unlocked before they can be used during the session.

To enable this protection, open File > Accounts… > Manage accounts > Credential protection…, then click Enable master password…. It protects stored secrets, but does not encrypt account names, account settings, or Access Key ID values.

If you use AWS profile or AWS default credential chain, their secrets are not stored in S3Client’s vault: their protection is handled by that source. See credential protection for details.

Is S3Client fast?

Yes. Speed is a priority for S3Client. It is designed to handle many tasks in parallel, meaning at the same time. Its engine can run hundreds or even thousands of operations simultaneously, depending on your settings, your computer’s resources, and the S3 service’s limits.

It coordinates the steps of each action, running independent operations in parallel. When an operation needs the result of another, it waits for that operation to finish before starting the next one.

This parallelism applies to file transfers, server-side copies, and property updates across many files. Large files can also be uploaded or downloaded in parts processed simultaneously, when the service and your settings allow it. This helps make better use of your network connection.

You can set the number of simultaneous operations in Tools > Options… > Operations. Actual throughput also depends on your connection, disk, and storage service: increasing that number does not always make operations faster. See the performance settings to adjust parallelism for your needs.

Why do some images have no preview?

S3Client’s built-in preview does not yet support every image format. The current Windows version can preview the following formats:

Even a file in a supported format may have no preview if it exceeds the configured size limit, cannot be read, or contains data the viewer cannot decode. See previews and their limits to understand the message shown.

For audio and video, the file format alone is not enough: playback also depends on the codec, which is the method used to encode the sound or video.

For other formats that contain text, you can enable previews by checking Text content in the mapping editor under Tools > Content types…. This setting is shared by extensions mapped to the same content type; recognized images, PDFs, and media keep their dedicated viewers. See configuring content types for the steps.

S3Client will evolve to support more preview formats.

How do I transfer my S3Client account to a new computer?

You can export one or more accounts to a .s3client.json file, then import them on the new computer. The export contains their configuration; your files remain on the storage service.

To include credentials stored by S3Client, first enable a master password. It will encrypt the export file, and you will need it to import the file. You can also export without these secrets and enter them after importing.

1. On the old computer, open File > Accounts…, then click Manage accounts > Export accounts…. Leave only the accounts you want to transfer checked.
2. Choose the destination file with Browse…. To include stored secrets, check Include stored Secret Access Keys and Session Tokens and enter Current master password. Otherwise, leave the checkbox unchecked. Click Export and check that the file was created.
3. Copy the file to the new computer, then open File > Accounts… > Manage accounts > Import accounts…. Choose the local file under Account export file. If it is encrypted, enter Source master password and click Unlock. If a destination password is requested and differs from the source password, uncheck The destination uses the same master password and enter Destination master password. Then click Import accounts, or Enable protection and import if shown.
4. Imported accounts are disabled. For each account, open Edit…, check the credentials, and enter any missing secrets. Use Test connection, save with OK, then choose More > Enable to see the account in the S3 browser.

If the new computer does not yet have a master password, importing secrets enables the password used for the export. If it already has one, its existing protection is retained, and you may be asked for that password.

Credentials from an AWS profile or the AWS credential chain are not copied: their source must be configured on the new computer. For these cases and the full procedure, see importing and exporting accounts.

Is S3Client affiliated with Amazon or AWS?

No. S3Client is independent software developed by Almageste. It is not affiliated with Amazon or Amazon Web Services (AWS), nor is it endorsed or sponsored by Amazon or AWS. Its compatibility with Amazon S3 simply means you can use it to access that storage service.

Amazon S3 and AWS are trademarks of Amazon.com, Inc. or its affiliates.