World Express — a rail fortune game

World Express is a free, browser-based multiplayer board game in which 2–4 players roll dice to travel a real railway map, buy businesses in real towns, answer geography quizzes, and race to a destination — playable in English, Spanish, French and Japanese across 48 boards covering six continents, the whole globe and the solar system.

▶ Play it in your browser — no install, no account, no ads.

A mirror also runs at grand-express.vercel.app; the link above is the canonical one.

This game was built almost entirely by AI agents (Claude Code) under human direction — including the clean architecture design, TDD test suite, and CI setup. It is part of an experiment in AI-orchestrated software development.

Stack: Next.js (App Router) · React · TypeScript · Zustand · Vitest · Playwright · dependency-cruiser · deployed on Vercel.

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What it is

You and up to three others — human or CPU, all on one screen — ride the rails. Each turn you roll, move along real railway lines, and land on a square:

• A town. Buy a business there. Own every business in a town and its income doubles.
• A quiz. Answer a question about the place you are standing in. Get it right, get paid.
• Fortune squares. Something happens that could plausibly happen there — a monsoon delay in Kerala, a strike in Buenos Aires, a customs hold at a break-of-gauge border.

First to reach the destination gets paid. The traveler in last place picks up a spirit of misfortune, drawn from that region's own folklore, who rides along and makes everything worse until someone else falls behind.

48 boards

Six continents (Europe, Asia, Africa, North America, South America, Oceania), a whole-globe board, the solar system, and country and regional boards including Japan, Bolivia, India, France, China, Brazil, Canada, Australia, Ukraine, Morocco, Ghana, Turkey, Korea, Malaysia, Indonesia, Bali, the Philippines, Ibaraki Prefecture and Japan's Hundred Famous Mountains.

2,261 towns and 3,949 quiz questions, each written in all four languages. Every town card carries something true and specific about that place — not a tourist blurb. Where the history is ugly, it says so plainly rather than skipping it.

Put it on your phone

Open https://t29mato.github.io/world-express/ on the phone, then:

• iPhone / iPad (Safari) — share button → Add to Home Screen → Add
• Android (Chrome) — the ⋮ menu → Add to Home screen / Install app

It gets its own icon and opens without an address bar. It runs offline — boards you have opened before stay playable with no connection. When a new version is out, the game says so at the bottom of the screen and waits for you to press Update; it never swaps itself while you are mid-game.

Run it locally

npm install
npm run dev            # http://localhost:3000

Command	What it does
npm run dev	Development server
npm run build	Production build
npm run test	Unit and component tests (Vitest)
npm run test:e2e	End-to-end tests (Playwright; run npx playwright install chromium once first)
npm run lint / npm run typecheck	ESLint / TypeScript
npm run depcruise	Enforces the Clean Architecture dependency direction
npm run check	Everything above, plus build and E2E — the same gate CI runs
npm run shot -- japan overview	Screenshot a board from the running dev server
node scripts/extract-legacy-content.mjs	Rebuild content JSON from the authoring sources

How it is put together

src/
  domain/           Game rules. Zero dependencies, zero framework.
  application/      Use cases and port definitions.
  infrastructure/   Content JSON, localStorage, audio, randomness.
  presentation/     Zustand stores and React components.
app/                Next.js App Router — routing only.
scripts/countries/  Authoring sources for each board (cities, routes, quizzes, art).
docs/               Architecture notes, ADRs, testing strategy, authoring guides.
legacy/             The original single-file HTML version, frozen as the behavioural spec.
e2e/                Playwright tests.

The dependency direction is not a convention here — dependency-cruiser fails the build if an inner layer reaches outward. 127 test files cover the domain rules, the content pipeline and the rendered board.

Board content is generated: scripts/countries/<board>/ and scripts/content-overrides/ are the sources, src/infrastructure/content/*.content.json is the output. Never edit the output.

Design notes and the migration history are in docs/ (written in Japanese).

About the experiment

The game began as one 2,964-line HTML file. Everything since — the Clean Architecture split, the DDD domain model, the TDD suite, the CI gate, the content pipeline, the 48 boards, the SVG artwork and the procedural music — was produced by AI agents working under human direction, often several agents in parallel on separate boards with a human and a coordinating agent reviewing what came back.

That review mattered. Agents shipped questions whose answers were already printed on the town card the player had just read, called Sedna a dwarf planet, and dated Japan's record wind gust to the wrong typhoon. Those were caught by measuring rather than by reading — the repository carries the checking scripts (scripts/check-quiz.mjs, scripts/check-sea-routes.mjs, scripts/check-city-backgrounds.mjs, scripts/check-quiz-risky.mjs) that exist because each of those failures happened at least once.

Licence

No licence has been chosen. Default copyright applies: the source is published to be read, and no permission to reuse it is granted. If you want to use any of it, open an issue and ask.

Town descriptions, quiz questions and artwork were written for this project. Place names, railway facts and historical events are, of course, nobody's property.