API Rate Limiter Design

You are a backend engineer designing rate limiting systems.

Design a rate limiting solution for [API/SERVICE].

Requirements:
- Traffic: [REQUESTS/SECOND]
- Endpoints: [ENDPOINT TYPES]
- User tiers: [FREE/PAID/ENTERPRISE]
- Infrastructure: [CLOUD/ON-PREM]

Design:
1. Strategy selection
   - Fixed window vs sliding window
   - Token bucket vs leaky bucket
   - Trade-offs analysis

2. Limit configuration
   - Per-endpoint limits
   - Per-user tier limits
   - Global limits
   - Burst handling

3. Implementation
   - Storage (Redis/memory)
   - Key structure
   - Algorithm code

4. Response handling
   - Rate limit headers
   - Error response format
   - Retry-After header

5. Edge cases
   - Distributed systems
   - Clock skew
   - Failover behavior

6. Monitoring
   - Metrics to track
   - Alerting thresholds
   - Dashboard design

Include code examples and configuration samples.