Native sync for
humans and agents
Bring your entire organization's workspaces directly to your desktop. A beautifully crafted native experience for Mac and Windows (coming soon).
Download for Mac
Download for WindowsComing soon4 deals totaling $283,000 are set to close by end of month. Acme Corp ($84K) and Northstar ($96K) are the largest.
Contracts Q2
Fastio Site
Fastio Folder
Application
Dashboard
Organizations
Settings
Troubleshooting
Theme: Auto
Logout
blake@northstar.co
Fastio
Network
The Engine Room for your Work
We rebuilt the desktop syncing experience from the ground up for the era of agent-human collaboration.
Native Filesystem Integration
View all your organization's workspaces directly in Finder (Mac) or File Explorer (Windows, coming soon). No more context switching.
Selective Sync
Keep massive workspaces in the cloud while retaining instant metadata access. Only download the exact files you need offline.
Unified Activity Stream
A beautiful native activity feed. See precisely what your team and AI agents are modifying across all synced folders in real-time.
Always Available Offline
Boarding a flight? Pin entire workspaces or individual files for offline use. Changes automatically sync when you reconnect.
Agent Interactions
Agents have workspaces, and now those workspaces live on your desktop. See model outputs and drop in inputs frictionlessly.
Blazing Fast Performance
Built with native frameworks for peak efficiency. Designed to seamlessly handle millions of files with zero battery drain.
Lives in Your Filesystem
Fastio mounts your workspaces straight into the file browser you already use, Finder on Mac and File Explorer on Windows (coming soon). You get the speed of local files with the capacity of cloud workspaces, and every file, agent output, and team asset opens the way any other folder does.
- Every workspace you belong to, mounted like a local drive
- Selective sync keeps large workspaces in the cloud
- Pin files or entire workspaces for offline use
Fastio
Network
Acme Holdings 8/4/26 -- Folder Bright Lane Media 7/22/26 -- Folder Meridian Ops 8/12/26 -- Folder Northstar Group 6/30/26 -- Folder 
Shared with me 8/1/26 -- Folder VividEngine 7/9/26 -- Folder 
Client Success 7/28/26 -- Folder Design 8/5/26 -- Folder Marketing 8/2/26 -- Folder Operations 7/15/26 -- Folder Revenue 8/13/26 -- Folder Status Reports 5/26/26 -- Folder Unified Activity Stream
Keep an eye on what's happening. The beautiful native activity monitor tracks every file creation, deletion, and modification. Watch your AI agents and teammates work in real-time as they edit your workspace.
- Every creation, edit, and deletion as it happens
- See what teammates and agents changed, and when
- Runs natively, no browser tab to keep open
Fastio Site
Fastio Folder
Application
Dashboard
Organizations
Settings
Troubleshooting
Theme: Auto
Logout
blake@northstar.co Common questions, answered.
Which operating systems does the Fastio desktop app support?
macOS today, with Windows coming soon. On a Mac your workspaces mount into Finder, and on Windows they will appear in File Explorer. In both cases they behave like any other folder, so the apps you already use can open and save files there directly.
Do I have to download all my files to my computer?
No. You choose what lives on disk. Keep files on demand and content arrives when you open a file, keep files downloaded so they stay on disk once fetched, or keep an entire workspace local so everything in it is on your machine whether you have opened it or not. Files you have not downloaded still show up in the folder with their names, sizes, and dates.
How large can a file be?
Up to 40GB. Large files upload in chunks sized to your plan, and if a file exceeds the limit the app tells you rather than failing quietly. Interrupted uploads and downloads resume from where they stopped instead of starting over.
How quickly do changes from teammates or agents show up?
Within seconds. A file added or changed in the cloud, whether by you on another machine, a teammate in the web app, or an agent writing to the workspace, appears in your local folder shortly after it lands.
Can I control how much of my connection sync uses?
Yes. Upload and download concurrency are both adjustable in Settings, under Files and Sync. Uploads run 1 to 16 at a time and default to 4, downloads run 1 to 8 and default to 5, and changes take effect immediately. You can also pause uploads for a single organization without affecting downloads or your other organizations, or cancel all in-progress uploads at once.
What happens if two people change the same file at once?
Concurrent edits are resolved on the merits rather than by whoever happens to sync last, and a conflict copy is created when one is genuinely needed. If you deliberately replace a file on your own machine, that is treated as an overwrite instead of being diverted into a conflict copy. Deletes are confirmed with the server before anything is removed from your disk.
How do I see what the app has synced?
The Sync Activity view shows a live history of uploads, downloads, renames, and deletes, grouped by organization and workspace, so you can confirm a file moved rather than guessing. An Organizations view covers credit usage and billing status, including organizations you have been invited to by other teams.
How does the app stay up to date?
It updates itself. If you are running an older build the app prompts you, and you can choose between the stable and beta channels at any time from Settings.
Put Your Workspaces on Your Desktop
Install the desktop app and every workspace lands on your machine. Work in the apps you already use, and your team and agents see every change.