S3 Pro

The most powerful S3 Client for macOS


Seamless access to S3-compatible storage and Backblaze B2 from within any application.

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Introducing v2021.6.1 for macOS 11 Big Sur
Released June 17th, 2021

Revolutionary macOS 11 File Provider

Finder Image

macOS 11 Big Sur provides revolutionary technology that enables kernel-level on-demand file sync. S3 Pro is the first app to implement a File Provider that lets you access and browse cloud storage without taking up disk space. When you open or access files APFS triggers S3 Pro to download only the content you want, on demand.

Advanced S3 integration

S3 is the original, and still the the fastest growing cloud-storage back end and all. S3 Pro is the only client that provides deep integration into advanced S3 features such as permissions management, versioning, CORs setting, bucket policy and more.

S3 Pro lets you select which buckets you want accessible in your apps. Choose just what you need and ignore the rest.

Deeply integrated search

S3 Pro fully integrates with Spotlight search for content you've previously browsed along with a comprehensive full-library server side search inside the dropdown. Easily get right to what you need to with high speed server-side search.

Sync without using free space

One of the most unique aspects of S3 Pro is that the files you don't needlessly use up any free space on your Mac. Files get downloaded transparently when another app requests them or when you request them in Finder.

APFS, the Apple Filesystem, manages your content and will evict your locally downloaded content if spaces gets low on your device. And soon S3 Pro will let you manually pin files to prevent evicition.

Ridiculously fast Parallel Transfer

S3 Pro utilizes the same high-speed transfer engine developed over the past decade for ExpanDrive. With the File Provider interface S3 Pro can upload and download large numbers of files in parallel, achieving dramatically higher performance than any other solution on the market.

Deep Integration with Finder and macOS

S3 Pro shows up in the Finder Sidebar along with every open and save dialog, in any app. It works with posix apps from the terminal. The on-disk content resides in ~/Library/CloudStorage. S3 Pro fully integrates with Spotlight search for content you've previously browsed.

For help installing or uninstalling please visit our documentation.

Usage is subject to our License agreement.