Player Sign-in
The smallest sign-in that gets a player onto the wire: one call from the Game Instance in C++, or one small widget in Blueprint. Everything else about accounts and tokens is on the Authentication page.
Map Profiles
The data asset that switches the SDK on for a map, how the SDK finds it, what each field controls, and the one field the shipped default leaves empty.
Entities and Spawning
Spawn an entity at runtime so every client sees the same actor, destroy it everywhere, and understand how a remote client rebuilds an entity it has never met.
Entity Component
Every callable, event, and setting on UCrowdyEntityComponent, one line each, with the two examples that show the accessor family and the lifecycle events.
RPC Events in C++
Declare a CrowdyEvent receiver, generate its call site with CROWDY_EVENT, and know which parameter types, sizes, and references make it across the wire.
RPC Events in Blueprint
Tick Crowdy Replicates on a Custom Event, pick a recipient, and call it like any other event; the body runs on every recipient with no second node.
Recipients and Routing
The four CrowdyEvent recipients, what a chunk is and how far a spatial event travels, what reliable means on the channel path, and the targeted sends for callers with no actor.
Crowdy State
Mark a property CrowdyState and the owning client diffs it every tick and ships the change to every proxy; the five metadata keys, the notify, the keyframe, what a property may be and what is rejected at discovery, the static Mark Crowdy State Dirty nodes and the host push they become on an entity you do not own, host precedence, and how to see a property that silently dropped out.
Continuous State
Dynamic entity mode: the transform snapshot the owner sends every replication interval with nothing to write, when that default is enough, and the custom executor path for a snapshot that carries more.
Host Authority
The calls that ask whether this client is the elected host, host-owned world entities, the host subsystem and its event, and the server-validated check for the moments a local answer is not enough.
Ownership Transfer
Move an entity's owner at runtime with a request and a grant: the four static nodes, the two subsystem events, what happens to in-flight state, and why ignoring a request is the rejection.
Replicated Subsystems
Give a world or game-instance subsystem Crowdy State properties and CrowdyEvent functions by inheriting one of two bases, the enrollment order that must hold, and the two things a subsystem cannot do that an actor can.
Rendering Backends
How a remote entity's continuous state becomes something on screen: the two backends the SDK ships (the default actor pool and the Crowdy Mass Rendering Backend), the policy class you subclass to apply your own state struct, the pool policy, and how to write a backend of your own.
Channels
Named, non-spatial message groups: create and join one, ban a member, publish raw bytes to every member, receive them, and understand the session channel every client joins and the three kinds of traffic that ride it.
Connection and Reconnect
How the realtime connection comes up, what it reports while it is up, how it reconnects on its own when it drops, the two events a game reacts to, bundled sends, and the per-frame receive budget.
Video Frames
Receive another player's webcam frames as whole encoded images: bind once, read the bytes, tell senders apart by the exact id, and decode them yourself.