orOS

A static operating system in your browser. Live at useoros.online. Every way to get it is on useoros.online/download.

orOS is a desktop in a web page: a menu, a taskbar, notifications, a universal search (Ctrl+K) and 132 apps, from notes, calendar, writer, spreadsheet and mail to maps, music, a DAW, business tools and 37 games. It installs as an app (PWA), works offline, and keeps your data on your device. If you want your data on more than one device, it syncs through your own Dropbox or WebDAV / Nextcloud server, encrypted before it leaves the browser.

Get orOS

All of it is free (see Free forever), and none of it goes through an app store.

• In the browser: open useoros.online. Chrome, Edge and Brave can install it as an app with its own window.
• Windows and Linux installers (v0.2.0): a Windows setup (orOS-Setup-<version>.exe), an AppImage and a .deb, plus Scoop (scoop bucket add oros https://github.com/koulaxizis/oros-portable, then scoop install oros) and winget. Installed copies update themselves. See koulaxizis/oros-portable.
• orOS Portable (v0.1.0): run orOS from a USB stick on any Windows or Linux PC, with or without internet; the data stays on the stick. Same repo.
• Bootable USB (beta): start a PC straight into orOS, koulaxizis/oros-usb.
• Android: orOS and single apps as APKs from the download page, with updates through the orOS repository for F-Droid, Droid-ify and Obtainium.
• Single apps: many apps install on their own, with their own icon, sharing data with orOS on the same device.
• orOS Drive (v0.2.0): a native app for Windows, Linux and Android that mirrors chosen folders both ways into the encrypted orOS disk in your Dropbox, and can show the whole disk as a folder (Windows Explorer, Linux, the Android Files app). koulaxizis/oros-drive.

Principles

• Offline first. Every app works without a connection. A service worker keeps the whole system on the device; online features (weather, maps, radio, TV, media search) say so and degrade gracefully.
• Your data stays yours. Data lives in the browser (localStorage / IndexedDB / OPFS). Optional sync goes to your Dropbox app folder or your WebDAV server (Nextcloud, ownCloud, Synology and others), end-to-end encrypted (AES-GCM, key from your passphrase via PBKDF2, 600,000 rounds). Neither the provider nor anyone else can read it. You can move between providers and restore any of the last cloud backups from Settings.
• Sync that never loses data. Each app merges changes from all devices (per-item last-writer-wins with tombstones), so editing on two devices never silently overwrites one of them.
• No cookies, no tracking, no analytics, no ads. No third-party scripts are loaded; every library is bundled in the repository. orOS depends on no Google service: fonts are bundled, there is no speech recognition that sends audio away, and read-aloud uses only voices on the device.
• Safe with untrusted content. Imported files, mail and anything from an online service are treated as hostile: sanitised in inert documents, shown as text, never executed. Every page has a Content-Security-Policy.
• Languages. English and Greek throughout; German as a third language (translator packs in i18n/, needs native review). New languages are welcome, see docs/translate/.
• Phone to desktop. Layouts work from 360 px wide up to large screens, with keyboard shortcuts on desktop (Ctrl+Alt+Shift+I shows them all).

Apps

All 132 apps, by menu category:

Category	Apps
Accessories	Weather, Time, Moon & Sky, Files, Calculator, Text Tools, Unit Converter, Sticky Notes, Case Converter
Office	To-Do, Kanban, Mind Map, Whiteboard, Notes, Wiki, Calendar, Contacts, Storage, Spreadsheet, Writer, Layout, Slides, Public Domain Calculator, QR Generator, orOS Converter, Scanner & PDF
Lifestyle	Minimalism, Split, Travel, Chore Wheel, Meal Planner
Learning	Flashcards
Business	Quote, Timesheet, CRM, Stock, Invoices, Newsletter, Email Signature, Certificates
Creativity	Prompter, Typewriter, Label Maker, Characters, Name Generator, Atelier, Mockups
Image	Photo Lab, Screen Capture, Pixel Avatar, Wallpaper Generator, Tree Sketcher, Aura Painter
Personal	Mood, One-Sentence Diary, Habits, Micro-Zen, Health, Budget, Water, Workouts, Cycle, Pet Health Book, Baby, Family Tree, Garage, Plant Care, Media Shelf, Library
Internet	Bookmarks, Maps, Reader, One-Minute Museum, Mail
Fun	Dice & Coin, Wheel of Fate, Oracle, Netizen ID, Pet World, Score Keeper
Sound	Radio, Podcasts, Music, Sound Mixer, Ringtone Composer, Studio
Video	Television, Montage
Games	Memory, Connect 4, Dots & Boxes, Tic-Tac-Toe, Simon Says, Number Slider, Lights Out, Whack-a-Mole, Snake, 2048, Wordle, Spot the Difference, Hexagon Puzzle, Chess, Sudoku, Tetris, Minesweeper, Mahjong, Gomoku, Bubble Shooter, Checkers, Mastermind, Battleship, Rock Paper Scissors, Hangman, Flow Free, Nonogram, Breakout, Reversi, Mancala, Pong, Backgammon, Word Search, Solitaire, Jigsaw, Crossword, Xeri, Game Center
Security	Passwords
System	Device Info, Assistant, Help, Today, Settings

Apps talk to each other (send a note to Writer, a contact to Mail, an invoice to Budget), open files by type, and share one encrypted disk in Files. Many open and save open formats (ODF, ICS, vCard, CSV, PDF and the documented orOS bundle format). The games and several apps are full rewrites of tablogames.online and soffitta.site.

Run it yourself

orOS is plain HTML, CSS and JavaScript with no build step and no dependencies to install. Serve the repository root with any static web server, for example:

python3 -m http.server 8000
# then open http://localhost:8000

• Service workers need https:// or localhost.
• Dropbox sync uses the orOS Dropbox app key in sync.js and redirects back to the page that started it. To self-host sync on another domain, create your own Dropbox app (scoped, App folder access, PKCE) and put its key in DROPBOX_APP_KEY.
• Mail (IMAP/SMTP), notifications while orOS is closed (Web Push), share links and WebDAV servers without CORS go through a small stateless relay; its code and deploy steps are in relay/. You can run your own on Cloudflare Workers.

Development

• Layout: the shell lives at the root (index.html, shell.js, sync.js, notifications.js, fs.js, vault.js, dialogs.js, pet.js, search.js, i18n.js, sw.js, style.css, translations.js); each app is a folder with its own index.html, loaded in a frame. apps.json is the app list. android/ is the Android app, extension/ the "Send to orOS" browser add-on.
• Tests: node --test tests/*.test.js (Node 22, no packages). They run in GitHub Actions on pull requests that touch tested code.
• Versions: APP_VERSION in shell.js is the only version set by hand. A GitHub Actions workflow stamps the service worker cache, the manifest and every asset's ?v= from it, and checks offline coverage and the app list.
• Project memory: OROS_BIBLE.md holds the architecture, rules, data models, decisions, open items and the changelog. Read it before changing anything.
• Credits: every library, font, icon set, data set and online service is listed in CREDITS.md and in the app (Info → Credits & licences). A change that adds one updates both.

Contributing

Fixes and new apps are welcome as pull requests; Christos decides what goes in, so open an issue with the idea first. See CONTRIBUTING.md. To build an app, the orOS App Kit has the app contract, a template and a local check that runs the same guards as CI.

How orOS is made

For full transparency:

• Christos Koulaxizis designs orOS, decides what it does and how it looks, tests it on real devices and reviews and merges every change.
• Lumo (Proton's AI assistant) helped write and shape the code of orOS.
• Claude (Anthropic's AI assistant) audits the code and, since October 2026, writes many of the new apps, fixes and tests as pull requests, under Christos's direction. Nothing reaches main without his review.

Designed with <3 by Christos Koulaxizis. Assisted by Lumo. Audited by Claude.

Free forever

orOS is free and open source (MIT), and it stays that way: no app or feature that has been released for free will ever be moved behind a paywall, and there are no license keys, ads or nags inside orOS.

Support

If orOS helps you, you can buy Christos a coffee on Ko-fi, or become a monthly supporter. The same Ko-fi page supports all of Christos's open-source projects (noxpress, NULL JSFX and orOS).

Need a hand? You can book a service on Ko-fi: orOS set up on your own domain with your own sync, your logo and app list, or a custom app.

Licence

orOS is released under the MIT License, © 2026 Christos Koulaxizis. Bundled third-party libraries, fonts, icons and data keep their own licences, listed in CREDITS.md.

Disclaimer

Use at your own risk. orOS and all its apps, sync, installers, orOS Portable, the orOS USB, orOS Drive and the Android apps are free software, provided "as is", without warranty of any kind. You are responsible for your own data: keep backups and keep sync turned on. To the fullest extent permitted by law, the makers of orOS and its contributors accept no liability for any loss of data or any other damage arising from the use of orOS. The same text, in English and Greek, is in the privacy policy.