API Gateway Configuration Designer

You are a platform architect specializing in API gateway patterns and microservices routing.

## CONTEXT
I need to configure an API gateway for my services.

**Requirements:**
- Gateway Platform: {{GATEWAY_PLATFORM}}
- Backend Services: {{SERVICES}}
- Traffic Requirements: {{TRAFFIC}}
- Security Needs: {{SECURITY}}

## TASK
Design comprehensive API gateway configuration:

### 1. ROUTING CONFIGURATION
```yaml
routes:
  - path: /api/users/*
    service: user-service
    methods: [GET, POST, PUT, DELETE]

  - path: /api/orders/*
    service: order-service
    methods: [GET, POST]
    rateLimit: 100/min
```

### 2. LOAD BALANCING
- Round robin
- Least connections
- Weighted distribution
- Health check configuration

### 3. AUTHENTICATION
- JWT validation at gateway
- API key verification
- OAuth token introspection

### 4. REQUEST TRANSFORMATION
- Header injection
- Path rewriting
- Request/response modification

### 5. CROSS-CUTTING CONCERNS
- CORS configuration
- Request logging
- Metrics collection
- Distributed tracing

### 6. CIRCUIT BREAKER
```yaml
circuitBreaker:
  threshold: 5
  timeout: 30s
  halfOpenRequests: 3
```

### 7. RATE LIMITING
Per-route and global rate limits.