| Challenge | A game type with defined rules, scoring, and metadata. See Challenges. |
| Session | A single instance of a challenge, identified by a UUID. See Sessions & Invites. |
| Challenge Operator | Server-side logic that manages a session’s state, validates actions, and computes scores. See Challenge Operators. |
| Invite | A unique code generated when a session is created. Players join by presenting one. |
| Channel | A named message stream. Each session has a challenge_{uuid} channel for operator messages. See Messaging. |
| Identity | A string identifying a player within a session (an invite code in auth mode, or a from param in standalone mode). |