--- title: GitHub - bashalarmistalt/decimen-optical-transfer description: Decimen Optical Transfer is a browser-based tool that transfers files between devices using only a screen and a camera — no network, no app install, no pairing... canonical: https://daily.dev/posts/github---bashalarmistalt-decimen-optical-transfer-waospd39k twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: GitHub - bashalarmistalt/decimen-optical-transfer | daily.dev og:description: Decimen Optical Transfer is a browser-based tool that transfers files between devices using only a screen and a camera — no network, no app install, no pairing... og:url: https://daily.dev/posts/github---bashalarmistalt-decimen-optical-transfer-waospd39k og:image: https://api.daily.dev/og/posts/WAOSPd39K.png og:image:alt: GitHub - bashalarmistalt/decimen-optical-transfer og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # GitHub - bashalarmistalt/decimen-optical-transfer **[Hacker News](https://daily.dev/sources/hn)** · 3 min read · 3 upvotes · 0 comments ## Summary Decimen Optical Transfer is a browser-based tool that transfers files between devices using only a screen and a camera — no network, no app install, no pairing required. It encodes files as an animated stream of QR codes using Luby transform (fountain coding), allowing the receiver to reconstruct the file from any sufficient subset of frames in any order. Supports files up to 64 MB, preserves filenames and media types, applies gzip compression when beneficial, and verifies integrity with SHA-256. Achieved 128 KB/s phone-to-phone in testing. Works offline after first visit and can be installed as a PWA on iOS and Android. Not encrypted — the data is visible to any camera. Open source under MIT, built with node-qrcode and zxing-wasm. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How can I transfer a file between two devices with no shared network using QR codes? Display the file as a continuously animated stream of QR codes on one device's screen and have another device's camera read and reconstruct it, with no network, pairing, or app install needed. The sender streams fountain-coded frames using Luby transform coding, so the receiver only needs to capture roughly K·1.15 distinct frames in any order, and dropped frames only cost time rather than breaking the transfer. One implementation reached 128 KB/s phone-to-phone for files up to 64 MB. _daily.dev surfaces novel offline transfer techniques like this for developers exploring camera-based protocols._ ### Is optical QR code file transfer between devices encrypted? No, optical transfer over a screen-to-camera link is not encrypted by design; whatever appears on the sending screen is readable by any camera pointed at it. The property this approach provides is the absence of a network path, not confidentiality, so sensitive data should not be sent this way without separate encryption. _Developers weighing offline transfer options against confidentiality needs can track such trade-offs on daily.dev._ ### Why use fountain codes like Luby transform instead of sequential QR code chunking for file transfer? Fountain coding lets the receiver collect any sufficient number of distinct frames, roughly K·1.15, in any order to reconstruct the file, rather than needing every specific chunk in sequence. Since a screen-to-camera link has no back-channel to request missed frames, dropped frames under sequential looping cost correctness, while under fountain coding they only cost time. _daily.dev helps developers comparing streaming and coding strategies for lossy, one-way data channels._ ## Similar posts on daily.dev - [GitHub - unprovable/ShadowCat: Single file optical file transfer using a browser](https://daily.dev/posts/github---unprovable-shadowcat-single-file-optical-file-transfer-using-a-browser-m2qmhzhw7) · Hacker News · 60 upvotes · 3 comments --- Tags: [#webdev](https://daily.dev/tags/webdev), [#typescript](https://daily.dev/tags/typescript) [View this post on daily.dev](https://daily.dev/posts/github---bashalarmistalt-decimen-optical-transfer-waospd39k) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"GitHub - bashalarmistalt/decimen-optical-transfer","url":"https://daily.dev/posts/github---bashalarmistalt-decimen-optical-transfer-waospd39k","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/github---bashalarmistalt-decimen-optical-transfer-waospd39k"},"datePublished":"2026-08-06T11:13:01.625Z","dateModified":"2026-09-14T07:29:56.177Z","description":"Decimen Optical Transfer is a browser-based tool that transfers files between devices using only a screen and a camera — no network, no app install, no pairing...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/19d18a7e8622426259ce84bc43cbafc0?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/19d18a7e8622426259ce84bc43cbafc0?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Hacker News","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Hacker News","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/hn","url":"https://daily.dev/sources/hn"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/github---bashalarmistalt-decimen-optical-transfer-waospd39k","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":3},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"webdev,typescript","timeRequired":"PT3M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Hacker News","item":"https://daily.dev/sources/hn"},{"@type":"ListItem","position":3,"name":"GitHub - bashalarmistalt/decimen-optical-transfer"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/github---bashalarmistalt-decimen-optical-transfer-waospd39k#faq","mainEntity":[{"@type":"Question","name":"How can I transfer a file between two devices with no shared network using QR codes?","acceptedAnswer":{"@type":"Answer","text":"Display the file as a continuously animated stream of QR codes on one device's screen and have another device's camera read and reconstruct it, with no network, pairing, or app install needed. 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