Multiplayer Game Architecture

Build the multiplayer contract before writing netcode. The output is a reviewable multiplayer-contract.json, not a framework recommendation disguised as architecture. Topology, authority, replication, transport, session lifecycle, security, and tests must agree with one another.

When to use this skill

Use it to:

• design or review a new multiplayer game's networking model;
• retrofit multiplayer into an existing game without mixing client and server truth;
• choose authority and replication per state domain;
• compare browser or engine transports against actual delivery needs;
• define lobby, allocation, join, reconnect, late-join, finish, and shutdown behavior;
• investigate desync, prediction error, cheating, host migration, or network instability;
• turn vague goals such as "make it multiplayer" into an executable contract and test matrix.