About Tachy

What it is

You have something on one device and you need it on another. A photo on your phone that belongs on your laptop. A link, an address, a block of text you would otherwise retype. The usual answers all involve a detour — a cloud drive, a chat with yourself, an email you will have to delete later.

Tachy skips the detour. Drop the file in, get a six-character code, type that code on the other device. There is no account to make and nothing to install on either end.

How the code works

Each transfer gets six characters drawn from Crockford base32 — the digits plus every letter except I, L, O and U. The excluded letters are the ones that look like something else in most typefaces, so a code read off a screen and retyped by hand still resolves. Type an O where a zero belongs and it will still find your transfer.

That gives a little over a billion possible codes, and lookups are rate limited, so guessing your way onto someone else’s transfer is not practical. The code is only minted once every file has finished uploading, so a half-finished transfer can never be handed out.

What it will carry

• Up to 10 files in one transfer.
• Up to 100 MB per file, and 250 MB across the whole transfer.
• Text notes up to 100,000 characters, which is a great deal more than anyone pastes.
• An expiry of 1 hour, 24 hours or 7 days — 24 hours unless you change it.

You can also tick burn after download, which deletes the transfer the moment every file in it has been collected.

What it is not

Tachy is a courier, not a cupboard. Every transfer is deleted when it expires, and nothing is kept afterwards — there is no undo, no archive, and no way for anyone including us to bring a transfer back once it has gone. Do not use it as the only copy of anything.

Files are not encrypted end to end. Anyone holding the code can download the transfer, and whoever operates the server is technically able to read what passes through it. For anything genuinely sensitive, encrypt it yourself before you upload it. Our privacy policy sets out exactly what is stored and for how long.

Where transfers go

Files are held by the server so the two devices never need to be online at the same time. You can send from your phone, close the tab, and pick the transfer up on a laptop an hour later. Direct device-to-device transfer, which would skip the server entirely when both ends are live, is something we would like to add later.