colonizers‑core is a JavaScript library that implements the full game logic, state objects and serialization for “Colonizers,” an event‑driven digital version of the board game *The Settlers of Catan*. It provides a controller for validating player actions, a coordinator for updating the game state, a set of core game objects (board, tiles, players, etc.), and tools for building scenarios and converting the state to/from a JSON‑based save format, aimed at developers building online or offline Catan‑style games.