Android to Linux file transfer at AirDrop speed, over Wi‑Fi Direct

Linksy 0.9.9 sends big files from an Android phone to a Linux computer over Wi‑Fi Direct at 70 to 85 MB/s. Through the home router, the same phone and the same computer manage 15 to 20 MB/s. That's four times faster, a 4.8 GB video in about a minute instead of four or five, and it's the speed AirDrop reaches between the newest iPhones and Macs. It sets itself up for big files, needs no root and no settings, and the computer keeps its internet the whole time.

How fast is it, exactly?

We sent the same 4.8 GB video from a realme 15 Pro to a ThinkPad E14 (AMD Ryzen 5 5500U, MediaTek MT7921 Wi‑Fi 6 card, Fedora 44), with the two side by side on a desk, first through the 5 GHz home router, then over Wi‑Fi Direct. Linksy shows the speed while it sends; these are the numbers it showed over whole transfers, several times each.

The best run averaged 79 MB/s: 1.97 GB arrived in 25 seconds. Every byte is still checked against the sender's checksum before the file is saved, as with every Linksy transfer.

How does that compare with AirDrop?

Apple doesn't publish AirDrop speeds, and what people measure varies a lot with the devices and the distance. heise, the German tech magazine, describes about 4 MB/s as normal and 10 to 15 MB/s in the best conditions ("Wie funktioniert AirDrop?", 2022). Newer hardware goes much faster: a series of tests between an iPhone 15 Pro Max and M2 Pro and M3 Max MacBook Pros, posted on Apple's community site, found speeds up close of up to about 85 MB/s, falling by about half within five metres.

So Linksy over Wi‑Fi Direct, at 70 to 85 MB/s, is as fast as AirDrop at its best, and faster than the AirDrop most people get every day. To be fair to Apple: our numbers are from devices side by side too, and Wi‑Fi Direct slows down with distance and walls just like AirDrop does. The difference is that this works between an Android phone and a Linux computer, two devices Apple's AirDrop doesn't connect at all.

Why is the router so much slower?

Through the router, every byte crosses the air twice: phone to router, then router to computer. Both trips share the same channel, so they take turns. And each device only gets the speed of its own signal to the router: in our test the laptop sat a room away at -65 dBm, which gave it a 206 Mbit/s link, about 20 MB/s in practice. A browser download from the same router ran at the same speed, so the limit was the Wi‑Fi path, not Linksy.

Over Wi‑Fi Direct the phone and the computer make a Wi‑Fi network of their own. The file crosses the air once, over the short distance between the two, at the full speed both Wi‑Fi 6 radios can do. The diagram at the top shows the two paths.

How does Linksy set up Wi‑Fi Direct?

You don't do anything. When you send 256 MB or more, Linksy does this by itself:

1. The two devices agree over the connection they already have, on your Wi‑Fi or away from home.
2. The phone starts a Wi‑Fi Direct network and becomes its host; Android lets an app do that without asking you.
3. The computer joins it through NetworkManager, the program that already runs Wi‑Fi on most Linux desktops. No root, no password: the connection is your own, never saved, and gone when Linksy stops.
4. Linksy opens a second encrypted connection over the new link and sends the files on it. The first connection stays up for everything else.
5. Twenty seconds after the last transfer, the link closes by itself, so the phone stops hosting it.

Setting up takes about 15 seconds, most of it the two Wi‑Fi radios finding each other. If anything goes wrong, Linksy sends the usual way within 45 seconds and doesn't try again with that phone for ten minutes. Smaller files skip all this: the router path is already quick for them.

Does the computer lose its internet during the transfer?

No. Most Wi‑Fi cards can stay on your network and be on a Wi‑Fi Direct link at the same time, and Linksy never routes your internet through the phone. Your downloads, calls and browser keep using your router while the file goes the direct way.

Is it secure?

The Wi‑Fi Direct link is encrypted with WPA2, like your home Wi‑Fi. On top of that, Linksy's own connection is end-to-end encrypted with TLS 1.3, and only between devices you paired, the same as every other Linksy connection. A device that isn't yours can't join the transfer, and the link exists only while it's needed.

What do I need?

• Linksy 0.9.9 or newer on the computer, from the download section, as an .rpm, .deb, Arch package or Flatpak.
• NetworkManager and a Wi‑Fi card that does Wi‑Fi Direct. Most do. To check, run nmcli device: a device of type wifi-p2p means yes.
• The Linksy for Android update with Wi‑Fi Direct, on almost any Android phone.
• The two devices near each other, ideally in the same room.

It's on by default. To keep transfers on the router path, start the service with linksyd --no-direct.

Which phones and computers does it work with?

On the computer side, any Linux desktop where NetworkManager runs the Wi‑Fi: Fedora, Ubuntu, Debian, Linux Mint, Arch, openSUSE and most others, with GNOME, KDE Plasma or anything else, and the Flatpak too. The Wi‑Fi card and its driver must do Wi‑Fi Direct; Intel, MediaTek, Realtek and Qualcomm cards from the last several years generally do, and Linksy only offers it when the card says so. On the phone side, Android phones with Wi‑Fi Direct, which is almost all of them.

Two things it doesn't do yet. Two Linux computers can't make a direct link with each other: today the phone is always the one hosting it, so between computers files go through the router as before. And there is no iPhone app, so this is Android and Linux only.

How do I get the fastest transfers?

• Keep the two in the same room, a metre or two apart, with no wall or metal in between. Like every Wi‑Fi link, it slows down with distance.
• Put your router on 5 GHz. The phone usually opens its Wi‑Fi Direct link on the channel it already uses, so a computer on the same 5 GHz network doesn't have to switch its card back and forth between two channels.
• Plug the laptop in, and turn off the phone's battery saver: both can slow the Wi‑Fi down to save power.
• Send big batches in one go. The link is set up once, and it stays up for twenty seconds after a transfer, so the next file you send right away uses it too.

Can it go faster than 85 MB/s?

Not much on this hardware. Both test devices have Wi‑Fi 6 with two antennas on 80 MHz channels: at most 1,201 Mbit/s on paper, of which Wi‑Fi really delivers 60 to 70 percent, so about 90 to 100 MB/s in a perfect room. Phones and laptops with Wi‑Fi 6E or Wi‑Fi 7 can use 160 MHz channels, which doubles that, and Linksy picks it up by itself where both devices and Android allow it.

What we fixed on the way

The first tests didn't connect at all. Android hides a phone's own Wi‑Fi Direct address from apps and hands them02:00:00:00:00:00 instead, so the computer looked for a device that doesn't exist. It now finds the phone by its name among the Wi‑Fi Direct devices nearby, and only when exactly one has it. Then the link closed 20 seconds into a transfer: the receiving side thought it was idle. Both are fixed, with tests, and the details are in theprotocol notes. Linksy isfree and open source, so you can read every line of it.

What else does Linksy do?

Fast files are one part. Linksy also shares the clipboard, turns the phone into a webcam and a microphone, shows its screen, makes a tablet a second display, and much more, in one app. See how it compares with KDE Connect, or the three apps it replaces. More articles are onthe blog.