WispFile

How to send a large file to multiple people

By the WispFile team · Updated 24 September 2026

Share one link: everyone who opens it while you are online can download at the same time. The limit is your upload, because by default you send a copy to each person. With swarm mode, receivers pass pieces on to each other, so you upload far less.

Key facts

  • One link works for many receivers at once.
  • Each receiver normally costs you one full upload of the file.
  • Swarm mode: in our test, 10 receivers of a 20 MB file cost 40 MB of upload instead of 200 MB.
  • Swarm is opt-in per link, because receivers see each other’s network addresses.

Two ways to share with a group

ModeYour uploadBest for
StandardOne copy per receiverA few people, or people who should not connect to each other
SwarmAbout two copies, whatever the group sizeA team, a class, a crew

How swarm mode works

You serve the first receivers. Each of them keeps the encrypted pieces as they arrive and passes them on to later receivers, who can start while their “parent” is still downloading. Every piece is still checked by whoever finally decrypts it, so a bad relay is caught like a corrupt network. Turn it on when you create the link.

Frequently asked questions

Is swarm mode less private?

The files are just as encrypted. What changes is that receivers connect to each other and so can see each other’s network addresses, which is why it is off unless you choose it.

Do receivers need to be online at the same time?

They need you online. In swarm mode, a receiver passes pieces on only while their own page is open.

Can I see who downloaded?

Your sending page lists receivers and their progress; on Pro you also get an email when a download completes.

Related guides

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