Store the file, or never upload it: cloud transfer vs direct transfer

There are two ways to get a file to someone through a link in a browser. The common one uploads the file to a server and lets the recipient download it from there. The other never uploads it: the file streams straight from your browser to theirs. That one design choice decides almost everything else — how long the link works, who can read the file, whether the recipient has to be online, and what happens when the connection drops.

This page sets the two side by side, including the cases where the cloud approach is simply the better tool.

The short answer

A cloud transfer is a drop-off. You upload the file, the provider keeps it on its servers, and the recipient downloads it whenever they get to it, until the link expires.

A direct transfer is a handover. SaferDrop streams the file from your browser to the recipient's, encrypted end to end, while you both have the page open. No server ever holds a copy, readable or not.

If the recipient is not around right now, use a cloud transfer. If you are both available and the file should not exist anywhere but your two devices, use a direct transfer.

Side by side

Where a cloud transfer is the better choice

A direct transfer's guarantees come from not storing anything. That same property removes things a stored copy does well, and a comparison that skipped them would not be worth reading.

• The recipient can download later. A cloud transfer is asynchronous: you send tonight, they download tomorrow morning. SaferDrop has no inbox and no waiting file. Both of you must have the page open at the same time, and the sender cannot “leave a file” for someone to collect.
• The link lasts. A cloud link typically stays usable for days. A SaferDrop link is single-session: it expires within an hour, and once the transfer has happened, or the sender has closed the tab, there is nothing left to fetch. It is not a download URL.
• A failed download can be retried. Because the file is stored, a dropped connection on the recipient's side costs them a retry, not your time. An interrupted SaferDrop transfer cannot be resumed; without stored bytes there is nothing to resume from, so it starts over.
• One link, many people. A cloud link can usually be shared with a whole team. A SaferDrop link serves one recipient; to send the same file to five people, you run five transfers.
• Very large files. Paid cloud plans commonly go well beyond what SaferDrop handles. SaferDrop Pro stops at 2 GB per transfer.

Where a direct transfer is the better choice

• No copy outlives the handover. With a cloud transfer, the file sits on a server for as long as the link stays valid, and in backups for as long as the provider keeps them. With SaferDrop there is no such copy for a day, an hour or a second. If the link leaks next week, there is nothing behind it.
• The provider cannot read the file. Encryption at rest protects a file from outsiders, not from the service that holds the keys. SaferDrop encrypts each chunk in your browser with a key derived from a secret in the link's # fragment and a 6-digit PIN. The fragment is never sent to a server, so SaferDrop could not read your file even if compelled. See what zero-knowledge means.
• A leaked link is not enough. The PIN travels on a separate channel, such as a message or a call, and the link alone cannot decrypt anything. After five wrong PIN attempts the session closes.
• No upload to wait for. There is one trip instead of two. The recipient starts receiving as soon as the connection opens, instead of waiting for your upload to finish before their download begins.
• No monthly allowance to track. SaferDrop Free has no monthly count: one file of up to 100 MB per transfer, one transfer at a time, as often as you like.

Which one should you use?

Use a cloud transfer when:

• the recipient will download on their own schedule, not while you are sending;
• the same file goes to several people through one link;
• the file is larger than 2 GB;
• the content is not sensitive enough for a stored copy to matter.

Use a direct transfer when:

• you are both available now, on a call, in a meeting or during a handover;
• the file is sensitive (a contract, medical record, ID scan or unreleased work) and no copy should exist outside your two devices. See how to send confidential documents;
• you want to be sure the provider itself cannot open what you sent.

Plenty of people use both: a cloud link for the everyday “here are the photos”, and a direct transfer for the files that should never sit on anyone else's server.

How to send with SaferDrop

Open SaferDrop, add the file, then share the link and the PIN on separate channels. Stay on the page until the recipient has opened the link and the transfer finishes. Free transfers go up to 100 MB; Pro costs $12/month, or $10/month billed annually, and raises the limit to 2 GB with folders and multiple files. Encryption and the no-storage guarantee are identical on both plans.

For the general method on big files, see how to send large files securely.

Frequently asked questions