Decimen Optical Transfer

File transfer with no network

WHO USES ITAir-gapped rooms and locked-down networks · Handing a short text or file to an unfamiliar device · Developers curious about coding theory and in-browser camera work

Use in the browser

Send a file up to 64 MB between two devices using only a screen and a camera; no network.

★ 6.8klast 14 days · stars per dayhollow = no dataAs of 09-16 21:00 UTC

6,752 stars · checked on GitHub 09-15 19:34 UTC GitHub check 30 h late · no 7-day star increase observed (GH Archive) (as of 09-16 21:00 UTC)

RANKS MEDIA #15 As of 09-16 21:00 UTC

BACK CATALOG

A phone receiving a file from another screen's animated QR stream, showing 130.5 KB/s goodput and decoding about halfway done

TESIGN TAKE

An experiment that takes an old idea, moving bytes as light instead of over a network, to usable speed with fountain codes and nothing but a browser; it is upfront that there is no encryption, so any camera watching the screen can read it.

AT A GLANCE

WHY IT MATTERS

When there is no network between two devices, or none you trust, Decimen shows the file as an endless stream of animated QR codes and the other device's camera reads it back. A screen-to-camera link has no return channel, so it uses fountain codes (Luby transform): the receiver collects any ~K×1.15 distinct frames in any order, and dropped frames cost time, never correctness. A published record with its run report shows 1.0 MB in 2.5 s, 418.5 KB/s sustained, from a 49-inch monitor to an iPhone 17 Pro Max.

BUILD FROM THIS

Export a stream as an APNG or PNG sequence and drop it into a video lesson or a page: anyone pointing a camera at the playing file receives it. The source self-hosts with npm and also builds as two standalone pages, which fits air-gapped distribution.

WHO IT'S FOR

Air-gapped rooms and locked-down networks: pass a config file or document with only a screen and a camera
Handing a short text or file to an unfamiliar device: no account, pairing or cloud, just a browser on both sides
Developers curious about coding theory and in-browser camera work: open protocol docs and benchmark run reports

START IN 5 MINUTES

# 1. Open https://decimen.app/ on both devices — nothing to install; one side Send, the other Receive
# 2. To run it yourself:
# npm install
# npm run dev
# Open https://localhost:5173/send/ on the sending device and the printed Network URL on the receiving phone (accept the self-signed certificate once)

CAVEATS

AGPL-3.0-or-later licence (since v0.4.0; releases up to v0.3.0 remain MIT). AGPL obligations apply if you self-host or redistribute modified versions.
No encryption — any camera that can see the sending screen can read the file. Limits: 64 MB files, 4 MB text.
A web app (PWA) needing only camera permission; speed depends heavily on screen size and camera (phone-to-phone record is 199.2 KB/s). v0.5.3 per the homepage.

RECEIPT

SIMILAR TOOLS

Up to five from EXPERIMENT by ★ total: edited entries first, then repository cards; this entry is highlighted. Drawn from the same stored snapshot as the rankings — a comparison, not a recommendation. As of 09-16 21:00 UTC

NAME	★ TOTAL	▲ 7d	LICENSE	PLATFORM	LAST PUSH
Decimen Optical TransferFile transfer with no networkTHIS ENTRY	★ 6.8k	—	AGPL-3.0copyleft	web · ios · android	2026-08-26
quickguiNative GUI for Go, TS and Rust	★ 424	▲ +58	Licence unconfirmedunconfirmed	macos	2026-09-15
peerdAgent that runs inside your browser	★ 408	—	Apache-2.0permissive	web	2026-09-15
DuoFold for AndroidFold illusion for Android phones	★ 133	▲ +14	MITpermissive	android	2026-09-13
Programming MuseumEDUCATION	—	—	Licence unconfirmedunconfirmed	web	—