Gwent — The Witcher 3 card game

A recreation of Gwent as played in The Witcher 3: Wild Hunt (base game, Hearts of Stone, Blood and Wine and the next-gen update), against a computer opponent. It runs in any modern browser on PC and Android, installs as an app, and can be packaged as an Android APK.

How it works (same flow as the game)

1. Play: the home screen is plain black with the title, Play, a small How to Play link and the Music and Sound switches.
2. Deck builder: this is TW3's pre-match screen. Your deck for each faction is saved automatically, every time you change it, so next time you only edit it.
   • Switch faction with Q / E (LB / RB in the game) or by clicking the faction names.
   • Click a card in Card Collection to add it, or a card in Cards in Deck to remove it.
   • Filter with the row/hero/weather/special icons.
   • X (or click the leader) opens Choose a Leader.
   • Z, right-click or long-press zooms a card.
   • Enter starts the game, Esc closes.
   • The deck rules are TW3's: at least 22 unit cards and at most 10 special cards ("Special card limit reached").
3. Match: on the original board, with TW3's notifications, ability animations, sound effects and music.
   • Redraw up to 2 cards, then play.
   • Hold Space (or hold the [HOLD] Pass button) to pass.
   • Esc (or Menu) opens the menu: How to Play, music and sound, Restart Match, Change Deck, Forfeit Game (shown as a defeat) and Quit to Menu.
4. Results: Victory, Defeat or Draw with the round scores. Enter plays again, Esc goes back to the deck.

On phones and tablets, including the Android app, the hints are plain buttons without the keys. A card is zoomed by pressing and holding it, and How to Play explains only the touch controls.

Rules and content

• Factions: all 5, with their faction perks.
• Leaders: all 22, with their abilities.
• Cards: the full card list with original strengths, rows, abilities and copy limits.
• Abilities: Agile, Medic, Morale Boost, Muster, Spy, Tight Bond, Scorch (global and per row), Commander's Horn, Hero, Summon Avenger, Berserker and Mardroeme.
• Special and weather cards: all of them.
• Strength order: as in TW3: base → weather → Tight Bond → Morale → Horn. Heroes are never affected.
• Next-gen update: the Roach card is included.

Original assets and where they came from

All graphics, sounds and music are the original Witcher 3 Gwent assets, in www/assets/:

folder	contents	source
cards/lg	full card faces (previews, zoom, carousels)	asundr/gwent-classic, checked against matt77hias/Gwent
cards/sm	art-only textures for the board and hand, one per art variant	same
cards/db	deck-builder faces (blank parchment, name drawn in the game font)	made from cards/lg by tools/make_deck_faces.py
ui	board, notification emblems, gems, score tokens, icons, weather overlays, shields, card backs, end banners	gwent-classic
sfx	sound effects	gwent-classic
music	the five Gwent tracks from TW3's taverns and matches ("The Nightingale", "Back on the Path", "Another Round for Everyone", "A Story You Won't Believe", and the unreleased Gwent theme)	cut from a recording of the in-game Gwent music
fonts	D-DIN Condensed	Datto D-DIN, SIL Open Font License

Changes to the sources

• Only the assets were taken from those repositories, not their code or additions.
• Several leader cards in the source had their art paired with another leader's name. I checked each one against footage of the game's Choose a Leader screen and fixed them (tools/fix_leader_art.py).
• The card data was checked against the printed card faces.
• The board art is 16:9. On wider screens (most phones) its plain outer wood is mirrored to fill the sides (tools/make_board_sides.py), so the board reaches both edges of the screen.

Font. TW3's interface font is PF DinText Cond Pro, which is commercial and therefore not bundled. If it is installed on your system the game uses it; otherwise it uses D-DIN Condensed, a free DIN condensed that is very close.

The assets are the property of CD PROJEKT RED. This is a non-commercial fan project. Don't sell it or put it behind a paywall.

Play

• In a browser, on PC or phone: https://amilapoorna.github.io/Gwent/
• Android app: gwent.apk

Step-by-step instructions for players are in HOW_TO_INSTALL_AND_PLAY.md.

Publishing

Every push to master runs two GitHub Actions workflows:

• pages.yml publishes www/ on GitHub Pages.
• android.yml builds the release APK with Capacitor and publishes it as the latest release (gwent.apk). It signs the APK with the keystore in the repository secrets GWENT_KEYSTORE_BASE64 and GWENT_KEYSTORE_PASSWORD (alias gwent). Keep a copy of that keystore: Android only installs an update over an existing app when both are signed with the same key.

Running locally

npm start                              # serves www/ at http://localhost:8080
npm install && npm run android:build   # debug APK; needs JDK 21 and the Android SDK

Tests

npm test               # rule scenario tests + several hundred AI-vs-AI games checked for invariants
npm run test:browser   # complete matches played through the UI in Chromium, at desktop and phone sizes

test:browser needs npm i --no-save playwright-core, a Chromium build (CHROMIUM=/path/to/chromium) and the game being served (npm start).

Project layout

www/
  index.html            screens and board markup
  css/style.css         styling; the 1920×1080 stage (the size of the board art) is scaled to fit any screen,
                        and on wider screens the board and overlays reach the edges
  js/cards.js           card, leader and faction data, starter decks, deck rules
  js/engine.js          rules engine (pure, cloneable state)
  js/ai.js              computer opponent
  js/ui.js              board, card carousel, input, sound and music
  js/deckbuilder.js     deck builder (auto-saved decks per faction)
  js/main.js            app flow
  assets/               original card art, UI, sound effects, music; bundled font
android/                the Android app (Capacitor), built by .github/workflows/android.yml
.github/workflows/      GitHub Pages and APK builds
tools/                  scripts that produced the derived assets
tests/                  rule tests, self-play and browser playtests