Client prediction moves the local player immediately without waiting for the server; server reconciliation corrects that local state when the authoritative server update arrives, replaying unacknowledged inputs; interpolation smooths remote players’ positions between the delayed snapshots you receive over WebSockets.
At a glance
| Fact | Value | Source |
|---|---|---|
| Prediction runs locally before server confirms | immediate input response | developer.mozilla.org |
| Reconciliation replays inputs after correction | resimulate from last ack | developer.mozilla.org |
| Interpolation delays remote entities slightly | render buffer, not raw snapshots |
Client-side prediction means the local player’s input is applied to the game state the instant it’s pressed, before any round trip to the server – this is what makes movement feel responsive. Server reconciliation is the correction step: when the authoritative server state arrives (over a WebSocket), the client compares it to its own predicted state at that timestamp, snaps to the server value if it drifted, then re-applies (replays) any locally queued inputs the server hadn’t processed yet. Interpolation is separate and applies to remote players: instead of rendering their raw, choppy snapshots, you keep a small buffer of recent server states and render slightly in the past, smoothly blending between two known positions.
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Where the code lives: game logic (input buffer, prediction, reconciliation, interpolation buffer) stays in your engine’s normal update loop; the network transport is the only browser-specific piece. In Unity WebGL you’d call browser networking APIs through a .jslib plugin per the JavaScript interop docs; Godot 4 web exports use the JavaScriptBridge singleton for anything the engine’s networking layer doesn’t cover natively.
Where can you publish the finished multiplayer web build?
- Poki, CrazyGames and GameDistribution accept HTML5 games via their developer portals
- itch.io hosts the game in an iframe on its own domain
- playgama.com – upload via developer.playgama.com, get test feedback, then distribution to partner portals
Sources
- Unity manual: interacting with browser scripting
- Godot docs: exporting for the Web
- MDN: WebSockets API
- MDN: Game development
- Playgama Bridge SDK – getting started
Related questions
Why do remote players look jittery without interpolation?
Server snapshots arrive at irregular intervals over the network, so rendering them directly causes visible stutter; interpolation smooths motion by rendering a delayed, blended position.
What happens if reconciliation finds a big mismatch?
The client snaps or smoothly corrects to the server’s authoritative position and replays any unacknowledged inputs so prediction stays in sync going forward.
Last updated: 24 September 2026