---
name: multiplayer
description: "Multiplayer game development principles. Architecture, networking, synchronization."
allowed-tools: Read, Write, Edit, Glob, Grep, Bash
risk: unknown
source: community
---
# Multiplayer Game Development
> Networking architecture and synchronization principles.
---
## 1. Architecture Selection
### Decision Tree
```
What type of multiplayer?
│
├── Competitive / Real-time
│ └── Dedicated Server (authoritative)
│
├── Cooperative / Casual
│ └── Host-based (one player is server)
│
├── Turn-based
│ └── Client-server (simple)
│
└── Massive (MMO)
└── Distributed servers
```
### Comparison
| Architecture | Latency | Cost | Security |
|--------------|---------|------|----------|
| **Dedicated** | Low | High | Strong |
| **P2P** | Variable | Low | Weak |
| **Host-based** | Medium | Low | Medium |
---
## 2. Synchronization Principles
### State vs Input
| Approach | Sync What | Best For |
|----------|-----------|----------|
| **State Sync** | Game state | Simple, few objects |
| **Input Sync** | Player inputs | Action games |
| **Hybrid** | Both | Most games |
### Lag Compensation
| Technique | Purpose |
|-----------|---------|
| **Prediction** | Client predicts server |
| **Interpolation** | Smooth remote players |
| **Reconciliation** | Fix mispredictions |
| **Lag compensation** | Rewind for hit detection |
---
## 3. Network Optimization
### Bandwidth Reduction
| Technique | Savings |
|-----------|---------|
| **Delta compression** | Send only changes |
| **Quantization** | Reduce precision |
| **Priority** | Important data first |
| **Area of interest** | Only nearby entities |
### Update Rates
| Type | Rate |
|------|------|
| Position | 20-60 Hz |
| Health | On change |
| Inventory | On change |
| Chat | On send |
---
## 4. Security Principles
### Server Authority
```
Client: "I hit the enemy"
Server: Validate → did projectile actually hit?
→ was player in valid state?
→ was timing possible?
```
### Anti-Cheat
| Cheat | Prevention |
|-------|------------|
| Speed hack | Server validates movement |
| Aimbot | Server validates sight line |
| Item dupe | Server owns inventory |
| Wall hack | Don't send hidden data |
---
## 5. Matchmaking
### Considerations
| Factor | Impact |
|--------|--------|
| **Skill** | Fair matches |
| **Latency** | Playable connection |
| **Wait time** | Player patience |
| **Party size** | Group play |
---
## 6. Anti-Patterns
| ❌ Don't | ✅ Do |
|----------|-------|
| Trust the client | Server is authority |
| Send everything | Send only necessary |
| Ignore latency | Design for 100-200ms |
| Sync exact positions | Interpolate/predict |
---
> **Remember:** Never trust the client. The server is the source of truth.
## When to Use
This skill is applicable to execute the workflow or actions described in the overview.