FatCat — Wiki & Documentation

rocket_launch Quick Start

FatCat is a platform for transferring large files to the cloud (Cloudflare R2, Backblaze B2). Send files of several GBs, share them via a link or email, and manage your storage space.

1

Log in

Access the Dashboard with your email and password. If you don't have an account, create one via the registration page.

2

Drop your files

Drag and drop one or multiple files into the upload area, or click to select them. FatCat automatically handles chunking and multi-part upload.

3

Share the link

Once the upload is finished, copy the share link or send it directly via email to the recipient. That's it!

cloud_upload Sending files

The upload wizard

Sending files is done in 3 steps via the built-in wizard:

Step 1 — Selection: Drag and drop your files or click "Browse". You can add multiple files at once.
Step 2 — Options: Choose the storage provider (R2, B2) and the expiration duration (7 days, 30 days, or no limit).
Step 3 — Email: Optional — enter the recipient's email address to send them the link automatically. Your email is pre-filled to receive a copy.

Multi-part upload

Large files are split into 10 MB chunks and sent in parallel. The progress bar shows the overall completion state. In case of network interruption, the upload automatically resumes where it left off.

💡 Pro Tip: For very large files (> 2 GB), use the desktop app which has no size limits and offers maximum speed.

share Sharing & emails

Share link

Each uploaded file generates a unique download link. The recipient does NOT need a FatCat account to download the file — they just click the link.

Sharing via email

During upload, provide the recipient's email address. FatCat sends an email containing the download link. If you provide your own email, you also receive a confirmation copy.

File expiration

7 days: Ideal for quick temporary sharing.
30 days: For files to be kept for a while.
No limit: The file remains available as long as you do not manually delete it.

⚠️ Expired files are deleted automatically and cannot be recovered. Choose the expiration duration carefully.

desktop_mac Desktop App

The FatCat desktop application is a native wrapper that bypasses browser limitations. Advantages:

No size limit: Web browsers limit uploads to ~2-4 GB. The desktop app has no limits.
Faster uploads: Direct connection to our servers, without browser networking layers.
Auto-resume: If the connection drops, the upload resumes on its own.
System tray: Minimize the app in the menu bar (macOS) or the system tray (Windows).

Log In from the app

The desktop app has its own login form. Enter your email and password directly in the app to authenticate. You can also open the Web Dashboard using the "Open Dashboard" button.

Download the app

Go to the "Download" tab in your Dashboard to get the version corresponding to your system (macOS Apple Silicon, Windows).

dns Storage Providers

FatCat supports multiple cloud storage providers:

cloud

Cloudflare R2

Zero egress fees. Ideal for standard storage and frequent sharing.

backup

Backblaze B2

Extremely low cost. Perfect for cold data archiving.

💡 Recommendation: Cloudflare R2 is the default choice. Transfer is free and files are served via the Cloudflare CDN for ultra-fast downloads.

manage_accounts Account Management

Profile

Access the "Account" tab in the Dashboard to modify your email, change your password, and check your used storage space.

Storage Quota

Each account has a specific storage quota defined by the administrator. The usage indicator in the Profile tab shows your current consumption. Contact support if you need more space.

Security

Change your password regularly via the "Security" tab.
Your email must be unique — two accounts cannot use the same email.
Sessions expire after prolonged inactivity.

help FAQ

What is the maximum file size? expand_more

Via the web browser: around 2-4 GB depending on the browser. Via the desktop app: no limit.

Does the recipient need an account? expand_more

No. The download link is public — anyone with the link can download the file, without registering.

My upload got interrupted, what should I do? expand_more

Don't panic. FatCat saves the progress state. As soon as the connection returns, the upload automatically resumes. For extremely large files, use the desktop app.

How do I delete a file? expand_more

In the "Files" tab of the Dashboard, click the delete icon (trash can) on the right side of the file row. Deletion is permanent.

How is FatCat different from WeTransfer or Google Drive? expand_more

FatCat can be self-hosted, utilizes your own cloud storage instances (R2, B2), and gives you total control over your data. No arbitrary limits, no ads, no data reselling.

Is the desktop app available on Linux? expand_more

A Linux version (.deb) is in development and will be available soon. Meanwhile, the web version works perfectly on Linux.

FatCat Documentation