Question 1

Do my files get uploaded to a server?

Accepted Answer

No. They go from one device to the other over an encrypted connection. If a network blocks the direct path, an encrypted relay passes the data along without storing it or being able to read it. Nothing is stored, so there is nothing to delete afterwards.

Question 2

Is flies free?

Accepted Answer

Yes, and there is no account to make. Direct transfers between the two devices are not counted. When a network blocks the direct path, the encrypted relay carries up to 500 MB per device each month, sent and received combined, because relaying data costs money. If flies is useful to you, you can support it on Ko-fi.

Question 3

Is the transfer encrypted?

Accepted Answer

Yes, end to end. The connection uses DTLS encryption, and before anything is sent both devices show four symbols. If they match, no one is intercepting the connection. A network or relay in between only sees encrypted data.

Question 4

Does it work between an iPhone and a Windows PC?

Accepted Answer

Yes. flies runs in the browser, so any two modern browsers can connect: iPhone to Windows, Android to Mac, Linux to iPad. There is no app to install and no account to make.

Question 5

Do both devices need to be on the same network?

Accepted Answer

No. On the same Wi-Fi the transfer stays local; across the internet the two devices connect directly when they can, and use an encrypted relay when a firewall blocks the direct path. In settings you can disallow the relay, or require both devices to be on the same network.

Question 6

Is there a file size limit?

Accepted Answer

flies sets no limit. In Chrome and Edge on a computer, “Save to folder…” writes each file to disk as it arrives, so the limit is your free disk space. Other browsers keep a received file in memory until it finishes, so the limit is the device’s memory.

Question 7

How long does a pairing code last?

Accepted Answer

15 minutes. The code only exists so the two devices can find each other; once they are paired the code is no longer needed, and the session ends as soon as either device closes it.

Send a file between two devices without uploading it

Connect your two devices

Three steps to send a file

1Connect

2Verify

3Send

Four symbols show that no one is in between

What a server can see

What it can see

What it can’t see

What else flies does

Text and links

Several files, both ways

Straight to a folder

Your choice of network path

Why not AirDrop, LocalSend or WeTransfer?

Frequently asked questions

Try it now with a second device