Networking & replication

Unreal multiplayer is server-authoritative: the server holds the ground truth and replicates state to clients; clients send intent to the server via RPCs. Nearly every multiplayer bug is an authority or replication-setup mistake. Design state ownership first (gameplay-framework), then replicate it correctly.

When to use this skill

• Replicating actor state (health, ammo, doors, scores) to all clients.
• Letting a client ask the server to act (fire, interact, ability use) via an RPC.
• Choosing between Replicated vs ReplicatedUsing, or picking a COND_* condition.
• Setting up dormancy, net update frequency, or relevancy for performance at scale.
• Diagnosing "it works in PIE single-player but breaks in multiplayer".
• Adopting Push Model or FFastArraySerializer for efficient high-scale replication.

Authority and roles

Every actor copy has a role on each machine: