Versus

Rank anything by comparing two items at a time. Add text, images or colors, pick your favorite in each duel (buttons, keyboard or swipe), and let the ranking emerge.

Live: https://versus.steevepommier.com/ (en français; the app itself is at /app/), also on https://costardrouge.github.io/versus/, without publishing

Features

• Duels with buttons, arrow keys (← A, → B, ↓ tie, S skip, ⌘/Ctrl+Z undo) or swipe.
• Items of any kind: text, images (drag and drop or paste, downscaled in the browser), solid colors and gradients with an inline color editor. Paste a whole list (plain lines, Markdown, a spreadsheet row) to add it at once.
• Four scoring methods, switchable at any time without losing duels:

  Method	Algorithm	Best for
  Balanced (default)	Bradley-Terry, fitted on all duels at once, with a ± margin per item	Photos, products, anything that doesn't change
  Dynamic	Elo, duel by duel	Preferences that evolve over time
  Simple	Smoothed win rate	Readability
  Exact sort	Binary insertion sort	Settling a short list in the fewest duels

• Method comparison on the results page, to see where the ranking is still fragile.
• Demos built from fixed data (same items and duels for everyone), resettable and translatable.
• English and French, detected from the browser and switchable.
• A home page in English and French with live demos: a virtual pointer plays the app, six topics to try, the four methods on the same duels.
• Search and share ready: a head per page with hreflang, Open Graph cards in both languages, structured data, favicons for every platform, a bilingual sitemap and llms.txt, all generated from one file (see docs/seo.md).
• Light and dark themes that follow the system setting or can be pinned from the header; the choice is applied before the first paint.
• Installable and offline: a service worker keeps the app on the device, so it opens without a network; new versions are offered, never forced (see docs/pwa.md).
• Export and import: save your rankings and votes in a file, or one ranking to send, and open them in another browser, on another device or in the installed app.
• Rankings stay in the browser (localStorage); only what you publish is sent. Visits are counted with a self-hosted, cookie-free Umami, never loaded for visitors who decline (a switch on the legal notice, Do Not Track, Global Privacy Control), and never with a ranking's content or id (see docs/analytics.md).
• Published boards: publish a ranking, share the link, and let a crowd vote in real time (on versus.steevepommier.com; the GitHub Pages copy has no backend). See docs/published-boards.md.
• Notifications (Web Push, sent by the Worker with WebCrypto only): a voter is told when a vote closes, an author as voters come in and when a picture is reviewed; asked on a tap, never on arrival (see docs/published-boards.md#notifications).
• Share as an image: your ranking, the crowd's, you against the crowd, or a single duel, drawn in the browser in post, story or landscape format and handed to the system share sheet, the clipboard or a download. A board's link unfurls with its own card, a duel link with its two items.
• Moderation: visitors report a board (anonymously, with a reason); the publisher's page at /admin/ lists boards with their reports, hides or features them, removes items and takes boards down (see docs/published-boards.md#moderation).
• Pictures through review (off by default): when the publisher turns them on, a published ranking's pictures are sent for review and shown once approved from the moderation page; until then the items show as text.
• Official templates and a Popular section: fixed lists on divisive topics (consoles, languages, phones, pastries…) published as real boards everyone votes on, each with an indexable page (/t/<slug>/, /fr/t/<slug>/) listed in the sitemap once it has a crowd; the gallery's Popular section shows them with the boards the publisher put forward, to vote or start one's own ranking from.

Development

Requires Node.js 22 or newer; the project is developed and built on Node 26 (see .nvmrc).

npm install
npm run dev        # local server with hot reload
npm run check      # lint, typecheck, tests, build: what CI runs

This is the beginning of the README. Read the rest at the original. Read the full README ↗