Guide · OtterDrop

Share files between your phone and computer

Emailing a photo to yourself, or uploading a document to a cloud drive just to download it again on the laptop next to you, is a workaround. If both devices are on the same Wi-Fi, they can hand the file to each other directly.

What you need

• Two or more devices on the same Wi-Fi. Any mix of phones, tablets and computers. A home router or a phone's hotspot both work.
• A current browser on each. Nothing to install, no account.

Steps

1. Open drop.ottercraft.dev on the first device. It joins the room for your network automatically, and you'll see your own device listed with a made-up name.
2. Open the same address on the second device. From a phone, the quickest way is to scan the QR code on the first screen. After a second or two, each device shows the other in its list.
3. Share a file. On the device that has it, drop it onto the page or tap to choose it. It shows up in the list on every device in the room, but nothing has been sent yet.
4. Take it on the other device. Tap the file (or Download all for several). It travels directly from the sharing device to yours and lands in your downloads. On a phone you can then save it to Photos or Files as usual.

How it works

OtterDrop uses WebRTC, the same standard browsers use for video calls, to open an encrypted connection directly between the two devices. A small signalling service on Cloudflare helps them find each other: it puts everyone on the same network into a room and passes the connection handshake between them. It never receives the files. Those go device to device in small chunks, paced so the transfer copes with a phone that briefly drops off the Wi-Fi.

Sharing a file only announces it. The transfer happens when someone asks for it. So you can share a big video once and let three people take it in turn, each straight from your device.

When it doesn't connect

• You don't see the other device. Check that both are on the same Wi-Fi and that neither has a VPN on. A VPN puts a device on a different network as far as the room is concerned.
• A device shows "adrift", or a download fails. Guest, hotel and office networks often stop devices from talking to each other ("client isolation"). Put both devices on a phone hotspot, or a home network, and try again.
• A transfer stops partway. Files come straight from the device that shared them, so that device has to keep the page open until the download finishes.
• "Could not reach the room server". The network is blocking the connection, or you're offline. Refresh to rejoin once you're connected.

Compared with the alternatives

• AirDrop and Nearby Share are great inside their own ecosystems. OtterDrop works between an iPhone, a Windows laptop and an Android tablet in the same room.
• Cloud drives and email send the file to a server and back, count against a quota, and often compress photos. OtterDrop moves the original at Wi-Fi speed and stores nothing.
• A USB cable works if you have the right one and the right drivers. OtterDrop needs neither.

Things worth knowing

• A room holds up to eight devices.
• Closing the page leaves the room and takes your shared files with it. Nothing is kept anywhere.
• The connection between devices is encrypted end to end by WebRTC. Anyone on the same Wi-Fi can join the room, though, so on a busy shared network, check the device name before taking a file, and don't share what you wouldn't want the room to see.