Send any file to a person, and keep proof it flew
FlyaDoc hands a file from you to someone else and, when either of you asks for one, writes a signed receipt that the exchange happened. It does not read the file, and it does not keep the file.
How it works
1. You send it
Pick a file and get a link, or a six-character code to read out. A document, a photo, an audio note, a video — whatever you need to hand over.
2. They receive it
They open the link or type the code while you are both on the page, and the file goes straight from your browser to theirs. Each side computes a digest of what it handled and reports that digest back.
3. A receipt, if you want one
Both of you see whether the two digests matched. Whoever asked for a receipt is emailed a signed copy; if nobody asked, no receipt is written.
Both of you have to be there at the same moment for the handover above. If the other person is not around, your FlyaDoc inbox takes a file while you are away: they drop it at your address, it is locked before it leaves their browser, and only the browsers you have set up can open it.
Any kind of file
FlyaDoc is not just for paperwork. It carries the whole range of things people actually send each other:
What DocButterfly witnesses — and what it does not
DocButterfly is the neutral witness in the middle. It knows the exchange took place; it never has what was in it. When one of you asks for a receipt, the signed record holds:
- The parties — the two accounts that sent and received.
- The hashes — the digest both sides independently reported, and the size.
- The connection — the encryption fingerprints each browser saw, so the safety code can be checked later.
- A transaction id — the reference that resolves back to that record.
It never holds the file. It does see the file's name and size, because each browser reports them alongside its digest so the two sides can be matched, and the receipt you are emailed names the file. DocButterfly's transaction lookup leaves the file name and both email addresses out. If neither of you asks for a receipt, none is written.
Read the receipt wording carefully
It is deliberate. The receipt says both parties reported the same digest. It does not say DocButterfly checked the file, because DocButterfly never had the file. That is the honest claim, and it is the only one we make. If the two reported digests do not match, the receipt says that instead — it never reads as "complete" when the halves disagree.
Part of DocButterfly
FlyaDoc rides on the same platform as the rest of DocButterfly. Once a file lands, the same account can convert it, read it, pull the fields out of it, get it signed, or file it in a vault you control — from the portal or from your own code over a REST API. See how FlyaDoc works, or read about DocButterfly.
Get started
A DocButterfly account is free, and it is the only setup there is — nothing to install, nothing to configure.
Create a free accountWhat a receipt records
- Who sent and who received
- The digest both sides reported
- A transaction id you can reference
- Written only when one of you asks
- Never the file itself