PairOnce

LAPTOP ↔ LAPTOP · WINDOWS · MAC

Transfer files from one laptop to another, Windows to Windows or Mac to Mac, without a cable

Two Windows 11 PCs on the same Wi-Fi can use Nearby sharing, and two Macs can use AirDrop; both are built in.

When the computers are on different networks, one is a work or school machine, or the built-in sharing does not connect, open paironce.com on both, click Enter a code on one and type the six digits the other shows, then choose files and click Accept and Save.

Both computers need to be online at the same time, and a receiving Chrome, Edge or Firefox takes up to 2 GB per file; for something to pick up later, a cloud drive is the better tool.

Step by step

  1. Open PairOnce on both computers. Go to paironce.com on both. Chrome, Edge or Firefox on the receiving side takes big files; Safari on a Mac works for smaller ones.
  2. Pair them once. One computer shows a QR code and a six-digit code. On the other, click Enter a code and type the six digits; a code works once and lasts 10 minutes. Check that both screens show the same safety code, then click Approve device on the computer that showed the code.
  3. Choose the files on the sending computer. Click Choose files or drop files on the page: up to 100 files and 10 GB in total per selection.
  4. Accept and save on the receiving computer. Click Accept for each file, then Save. It lands in Downloads. Click I saved it so the sender knows it arrived.
  5. Next time, just connect. The other computer is listed under Your devices: open PairOnce on both and click Connect, with no new code.

Windows to Windows: what is built in

Nearby sharing sends files, photos and links to a nearby PC over Bluetooth or Wi-Fi. Microsoft lists Windows 11, Bluetooth with Low Energy support (4.0 or higher) and Bluetooth and Wi-Fi turned on for both PCs; turn it on under Settings › System › Nearby sharing. Over Wi-Fi the two PCs have to be on the same network (since an April 2024 update, public or private); otherwise it falls back to Bluetooth, within about 30 feet (10 meters).

A shared folder works across a network too: in File Explorer choose Share and give access to specific people, then connect from the other PC with Map network drive. Network discovery and file sharing have to be on. For sharing over the internet, Microsoft points to OneDrive.

Mac to Mac: what is built in

AirDrop needs Wi-Fi and Bluetooth turned on for both Macs and the two within 30 feet (10 meters). The receiver chooses Contacts Only or Everyone. From macOS 26.2, someone who is not in your contacts has to use an AirDrop code.

File Sharing, in the Sharing settings of System Settings, lets another computer on the same network connect to the Mac.

When the built-in tools are not enough

They stop at the edge of your network and your settings: two computers on different networks, a work or school computer where you cannot change settings or install anything, or a PC that does not meet the requirements above. PairOnce needs only two browsers and the internet.

Limits, and when this is not the right tool

  • A file can be up to 2 GB over a direct connection when the receiving browser saves straight to disk (Chrome or Edge on a computer or Android, Firefox on a computer, Safari on iOS 26 or later). Other browsers take up to 50 MB per file and hold 100 MB of received files at a time.
  • Files over 2 GB need PairOnce Pro on one of the two devices. Then a file can be up to 10 GB, received the same way, and the relay carries 5 GB a month.
  • When the two devices cannot reach each other directly, an encrypted relay carries the data. Each device can send and receive 200 MB a month that way, counted together; a direct connection has no monthly limit.
  • Both pages must stay open until everything has arrived: keep the phone’s screen on and the browser in front.
  • PairOnce moves things between two devices that are open at the same time. It is not cloud storage: nothing waits on a server for later.

Other ways to do it

  • A USB drive. Needs no network; copy on one computer, plug it into the other.
  • A cloud drive such as OneDrive or iCloud Drive. Upload on one, download on the other; works at any distance, but needs an account and the file goes through the cloud first.
  • Email or a messaging app. Fine for small files; attachments are limited.
  • LocalSend. Free and open source. It mainly works through its app on both computers, on the same network; its web version also stays on one network and does not work with the app yet.

Common questions

Do both computers need to be on the same Wi-Fi?

No, but the same Wi-Fi is fastest. On different networks PairOnce often still connects directly; if not, an encrypted relay carries the data, 200 MB a month per device, so for big files put both on one network.

How big can a file be?

Up to 2 GB per file when the receiving browser is Chrome, Edge or Firefox. Other browsers take up to 50 MB per file and hold 100 MB at a time.

Is anything stored in the cloud?

No. There is no cloud storage. Files go to the other computer, directly or through a relay that only forwards encrypted data and keeps nothing, and wait in its page until you save them.

What if one computer is a Mac and the other a Windows PC?

The steps are the same: PairOnce only needs a browser on each side and does not care which system it is.