Monitoring CDN performance is vital for ensuring fast, reliable, and secure content delivery. Key metrics to track include latency, cache hit ratio, bandwidth usage, error rates, and time to first byte (TTFB). Real-time monitoring tools like Pingdom, Google Analytics, and Splunk can help detect issues quickly. Multi-location testing identifies regional performance gaps and confirms edge server functionality. Optimizing caching strategies using proper headers and purging techniques enhances efficiency. Security monitoring, including SSL/TLS performance and DDoS detection, is also essential. Automated alerts and failover mechanisms help in quick issue resolution. Analyzing historical data and ensuring compliance with SLAs allow for continuous improvement. Effective monitoring maximizes CDN investment and meets user performance expectations.