Help & Support

FileFly is a free app for sending files between Windows, macOS, Linux, iPhone and Android on the same Wi-Fi or local network. Move files from PC to PC, Windows to Mac, or a computer to your phone without uploading them to the cloud. Once the app is installed, transfers work without an internet connection.

Free on Windows, macOS, Linux, iPhone, and Android. Install it on every device you want to share files between.

Windows: Windows 10 & 11; macOS: macOS 11 or later; Linux: Debian/Ubuntu (64-bit), or any distribution with Snap support; iPhone: Requires iOS 18 or later; Android: Requires Android 7.0 or later.

Desktop: Install and open FileFly on both devices and make sure they're on the same network. The other device appears under Available Devices. Drag a file onto it (or select the device and choose a file), then ask the person on the receiving device to accept the incoming transfer. That's it.

No. FileFly never asks you to create an account or sign in, and it doesn't use the internet to move your files. It only needs both devices to be on the same local network.

Work through this checklist — most cases are one of these:

• FileFly is open on both devices.
• Both devices are on the same Wi-Fi network (not one on guest Wi-Fi and one on the main network).
• Your firewall is allowing FileFly on port 23013 (see the firewall question below).
• Any active VPN is turned off — VPNs route traffic away from your local network.
• Client / AP isolation is disabled on your router (common on guest and public networks — it blocks devices from seeing each other).
• Press the refresh button to re-scan for devices.

FileFly listens on port 23013 for both device discovery and file transfers. If your firewall blocks it, devices won't find each other or won't be able to receive files. The first time you run it, allow FileFly when your operating system prompts you. On Windows, allow it for Private networks; on macOS, allow incoming connections if prompted; on Linux, make sure port 23013 isn't blocked by your firewall (e.g. ufw).

No. FileFly is designed for devices on the same local network. Both devices need to be on the same Wi-Fi or LAN subnet so they can reach each other directly. It does not transfer over the internet.

Yes. Wired, wireless, or a mix all work as long as the devices are on the same network subnet (for example, all connected to the same router).

Every transfer is consent-based for your safety. When you send a file, the receiving device shows an Incoming File Transfer prompt, and the person must accept before anything is sent. If they deny it (or don't respond), nothing is transferred.

Incoming files are saved to your download location, which you can see and change under Settings → Download Location. On macOS you may be asked to grant access to the folder you choose the first time — that's expected.

Desktop: There's no built-in size cap, so large files transfer fine — the practical limit is the free disk space on the receiving device. You can also send whole folders: drag one onto FileFly or use Add Folder, and it arrives on the other device as a folder, with the subfolders and everything inside intact.

Usually one of these:

• The receiver didn't accept the prompt in time, or it was dismissed — start the transfer again.
• One device went to sleep or dropped off Wi-Fi — keep both awake and connected, then retry.
• The receiving device ran out of disk space — free up space and resend.

How FileFly handles your data: files stay on your local network, there are no accounts, and the optional anonymous analytics are fully under your control.

Each device has its own identity key, and FileFly remembers (“pins”) it the first time you connect. If a device later presents a different key, you'll see a Device Key Changed prompt. This almost always means FileFly was reinstalled or reset on that device. If you trust the device, approve the new key; if you weren't expecting it, reject it.

A trusted device is one whose identity key FileFly has already pinned, so you aren't prompted again on every connection. To start fresh, go to Settings → Clear Trusted Devices. You'll then be asked to re-trust each device the next time it connects.

Open Settings → Device Name and enter a new name. This is the name other people see for your device in their Available Devices list, so pick something recognizable like “Alex's MacBook”.

Go to Settings → Download Location and choose Change to pick a new folder.

Yes. FileFly is available in 10 languages — English, Spanish, French, German, Italian, Dutch, Arabic, Hindi, Malayalam, and Chinese. Choose one under Settings → Language.

Use Settings → Clear Transfer History. This removes the list of recent transfers shown in the app; it does not delete any files you've already received.

This is almost always your network or firewall. Disable client/AP isolation on the router, turn off any VPN, and make sure FileFly is allowed through the firewall on port 23013. Guest and public networks frequently isolate devices and won't work. Restarting FileFly on both devices after changing these settings helps.

This means the receiving device no longer recognizes your identity key (often after a reinstall). Ask the person on the receiving device to approve the new key when prompted, then try the transfer again.

The receiving device usually isn't reachable on port 23013 — its firewall is blocking inbound connections. Allow FileFly through the firewall on that device (Private networks on Windows), then resend.

Email me at [email protected] with your operating system, FileFly version, and a description of what happens. The more detail, the faster I can help.