PairOnce

ALTERNATIVE · LOCALSEND

A LocalSend alternative that runs in the browser

LocalSend is a free, open-source app (Apache-2.0) that sends files between nearby devices over the local network, without internet; you install it on every device.

PairOnce is the browser version of that idea: open paironce.com on both devices, nothing to install. Devices on the same Wi-Fi appear at the top of the pairing card, and a QR code or six-digit code connects devices across networks, with end-to-end encryption and a safety code you compare.

Pick LocalSend when you want an app and the network has no internet at all; pick PairOnce when you cannot install apps, or the devices are on different networks.

Step by step

  1. Open PairOnce on both devices. paironce.com in any current browser on a phone or a computer.
  2. Connect. On the same Wi-Fi, the other device appears under On this Wi-Fi: tap Connect. On any other network, scan the QR code or type the six-digit code. A page opened from a QR code or link asks you to confirm first: tap Connect.
  3. Compare the safety code. Both screens show the same code; click Approve device.
  4. Send. Tap Choose files or Message or link; the other side accepts and saves. Next time, tap Connect next to the device and skip the code.

LocalSend and PairOnce side by side

LocalSend: a free, open-source app (Apache-2.0) for Windows, macOS, Linux, Android, iOS and Fire OS. Devices find each other on the local network and files travel directly over HTTPS, with no internet and no third-party server. There is also a command-line client, `localsend-cli`, and the app lists the devices it finds, or you can type a device’s address. Details are in the LocalSend README.

PairOnce: free, no ads, no account, in the browser on every device. Devices on one Wi-Fi find each other; a QR code or six-digit code connects devices across networks, directly when possible and through an encrypted relay otherwise. Everything is encrypted with AES-256-GCM before it leaves the sending device, and a safety code lets both people check they are talking to each other. From a terminal, `npx paironce send report.pdf` sends a file to a paired phone.

If a device does not show up in LocalSend

The LocalSend README lists what to check: turn off AP isolation on the router (guest networks often have it on), set a Windows network to private, allow local traffic in a VPN, allow port 53317, or enter the receiver’s address by hand.

With PairOnce the six-digit code and the QR code do not depend on any of these: they connect the two devices wherever they are.

Large files that carry on

Files go up to 2 GB each when the receiving browser is Chrome or Edge on a computer or an Android phone, Firefox on a computer, or Safari on iOS 26 or later.

If the connection drops in the middle of a file over 16 MB, the transfer continues where it stopped once the same two devices reconnect within 30 minutes, with both pages still open and the same browsers receiving.

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

  • LocalSend. The better fit when you want an app on every device and the network has no internet at all.
  • PairDrop. Free and open source in the browser; finds devices on the same network and pairs devices across networks. See the Snapdrop and PairDrop comparison.
  • AirDrop or Quick Share. Built in, between Apple devices or between Android phones and Windows PCs.
  • A cloud drive. Handy for files you want to keep or share with several people; the copy stays on a server.

Common questions

Does PairOnce work like LocalSend on the same Wi-Fi?

Yes. Open paironce.com on both devices and the other one appears under On this Wi-Fi; tap Connect and compare the safety code. Unlike an app, nothing is installed.

Can I use both?

Yes. They do not depend on each other: use LocalSend on a network with no internet, and PairOnce when a device cannot install an app or the devices are on different networks.

Does it work when the two devices are on different Wi-Fi networks?

Yes. Connect with the QR code or the six-digit code. The files go directly between the two browsers when the networks allow it; otherwise an encrypted relay forwards them without being able to read them. See sending between different Wi-Fi networks.

Is PairOnce open source?

The command-line tool is open source (Apache-2.0), and the protocol and the core library are published on GitHub at github.com/paironce.