The JSON API.

The surface is a thin facade, not the game. Phoenix exposes a JSON API that turns a request into a command on the systems and a read into a view, and it owns no game state of its own: there is no process per room, no in-memory copy of a game on the web tier. State lives where it belongs — on the Postgres floor, in the cache, in the Valkey tier — and the surface reaches for it.

A guess is a command that returns at once. The endpoint validates, charges, and enqueues, then answers with an accepted status while the scoring runs behind the boundary; the player’s request does not wait for a score. Reads go the other way, into privacy-safe views: a player can ask for their own attempts, their best total, and the leaderboard ranked by best total, and for nothing else.

The view is shaped at the boundary, not by trusting the caller. A response never carries another player’s guesses or the secret, because the query that builds it cannot reach them, so a curious client gains nothing by asking a different way. The same surface carries the idempotent webhook that confirms a star purchase, an endpoint among endpoints, while the game keeps moving only its own currencies.