Post
A networking technique that sends only the changes (deltas) between world states, slashing bandwidth usage.
Sending the full world state every tick wastes bandwidth. Delta compression computes the difference between the last acknowledged state and the current one, transmitting only what changed. Combined with bit-packing and priority queues (replicate closer/more-important entities more often), it lets modern multiplayer games run dozens of players with minimal bandwidth. The downside is that packet loss compounds: if a delta is dropped, the next one must either resend or reference further back.
Example
Unreal Engine and Source Engine both use delta compression as a replication primitive. Halo's netcode documentation described this technique in the early 2000s. Modern battle royales use priority-based delta compression to handle 100+ entities per tick.
Why it matters
Delta compression is what makes large-scale multiplayer economically feasible. Without it, a 64-player shooter would need enterprise-grade bandwidth per player. It is one of those fundamental techniques that shapes what kinds of games can even be made.
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