Send large files without uploading them

Cloud transfer services make you upload the whole file before the other side can start downloading it, and many cap free transfers at a few gigabytes. When both devices are online, sending directly avoids both the wait and the cap.

How tosstome handles large files

No size limit is set. Data streams in chunks with end-to-end acknowledgements, so the sender never runs far ahead of the receiver.
On a direct WebRTC connection the data never touches a server, so speed depends on the two networks between the devices.
When a direct connection is not possible, the relay forwards chunks as they arrive. It does not buffer the file and keeps nothing afterwards.

The one thing to watch: browser memory

A browser cannot write to your disk until you press Save, so the receiving tab keeps the whole file in memory until then. A few gigabytes is fine on most computers; on a phone, or for files of tens of gigabytes, it may not be.

For big files, receive on a computer with the command line inbox. It writes to disk as the data arrives, so memory use stays flat whatever the file size:

tosstome listen --dir ~/Videos/incoming

Then send from any browser using the inbox link, or from another terminal with tosstome send.

Tips for very large transfers

Keep both devices awake and the sending tab in the foreground. Phones pause background tabs.
Prefer the same Wi-Fi or Ethernet. A direct connection on a local network is the fastest path.
If the other person cannot be online at the same time, a peer-to-peer tool is the wrong fit. Use a cloud drive or a stored-link service instead.

Questions

Is there a file size limit?

tosstome sets no limit. A receiving browser holds the file in memory until you save it, so for files of several gigabytes the command line inbox is the better receiver, because it writes straight to disk.

Is it faster than uploading to a cloud drive?

Usually, because the receiver gets data while it is being sent instead of after a full upload, and on a local network the data never leaves it. Over the internet, speed is limited by the slower of the two connections.

Are my files uploaded or stored anywhere?

No. Files go straight from one device to the other over WebRTC when the networks allow it. When they do not, the file passes through a relay on Cloudflare that forwards the bytes as they arrive and keeps nothing. If the receiver is offline, nothing is sent.

Can the receiver download later?

No. Both devices must be online at the same time. That is the trade-off for nothing being stored.

Last checked 2026-10-28.

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