How Can I Test My Website's Performance After Migrating to a CDN?

To test your website's performance after migrating to a CDN, you should measure key CDN metrics like latency, load times, and overall user experience. 

‍

Use tools like Google PageSpeed Insights, GTmetrix, and WebPageTest to assess these aspects. Additionally, monitor real user data to get a comprehensive view of your site's performance.

‍

Here's how I approach testing my website's performance after moving to a CDN through a migration checklist.

‍

{{cool-component}}

‍

1. Baseline Performance Metrics

‍

First, you need to establish a baseline. Before migrating to the CDN, record your website’s performance metrics. Tools like Google PageSpeed Insights, GTmetrix, and WebPageTest are excellent for this. 

‍

Measure load times, First Contentful Paint (FCP), Time to Interactive (TTI), and overall page speed scores. This baseline will serve as a comparison point to evaluate the impact of the CDN migration.

‍

2. Use Synthetic Monitoring Tools

‍

After migration, the same tools used for baseline metrics will now help gauge the impact of the CDN:

‍

• Google PageSpeed Insights: This tool provides a comprehensive view of your site’s performance by measuring key metrics like FCP, Largest Contentful Paint (LCP), and Cumulative Layout Shift (CLS). The scores here reflect real-world performance data, offering insights into how users experience your site.
• GTmetrix: This tool offers detailed reports on your site's performance, including load times, total page size, and the number of requests. GTmetrix also provides waterfall charts that show how each element of your page loads, helping identify bottlenecks.
• WebPageTest: This is another robust tool for performance testing. It allows you to test your site from different locations worldwide and provides in-depth details about loading times, CDN usage, and resource loading sequences.

‍

3. Measure CDN Latency

‍

CDN performance is highly dependent on reducing latency. Tools like Catchpoint can help measure the latency introduced by your CDN. 

‍

These tools provide real-time data on how quickly content is delivered from various CDN nodes to users worldwide.

‍

4. Real User Monitoring (RUM)

‍

While synthetic tests are valuable, real user monitoring gives you insights based on actual user interactions. Tools like New Relic, Datadog, or Google Analytics can help:

‍

• Google Analytics: Enable site speed tracking to get data on page load times, server response times, and download times from real users.
• New Relic: Provides deep insights into your website’s performance, including browser load times, request rates, and error rates. It’s particularly useful for understanding how different regions experience your site.
• Datadog: Offers detailed performance metrics, including real user data, which can help you understand how CDN migration impacts users in various locations.

‍

5. Compare Pre and Post Migration Data

‍

Once you have collected data post-migration, compare it with your baseline metrics. Look for improvements in:

‍

• Page Load Times: A good CDN should significantly reduce your page load times by caching content closer to your users.
• Time to First Byte (TTFB): This metric indicates how quickly your server responds to requests. A CDN should lower TTFB by serving cached content.
• Overall User Experience: Metrics like FCP, LCP, and TTI should show noticeable improvement, indicating that users are able to interact with your site faster.

‍

{{cool-component}}

‍

6. Assess CDN Coverage and Efficiency

‍

Not all CDNs are created equal. Some may have better coverage in certain regions. 

‍

Tools like Cloudflare’s CDN performance checker or Akamai’s Real User Monitoring can help assess how well your CDN is performing in different geographical areas. Check for:

‍

• Regional Performance: Ensure that users from various regions experience improved load times. A CDN with a widespread network should show consistent performance improvements across different locations.
• Edge Caching Efficiency: Effective CDNs cache content at the edge servers. Tools that provide insights into cache hit and miss ratios can help you understand how well your CDN is performing. A higher cache hit ratio generally indicates better performance.

‍

7. Optimize Your CDN Configuration

‍

Sometimes, performance issues post-CDN migration might be due to suboptimal configuration. Here’s how I optimize CDN settings:

‍

• Cache Policies: Ensure your cache policies are correctly set. Static assets like images, CSS, and JavaScript files should have long cache durations, while dynamic content should have shorter cache times.
• Compression: Enable gzip or Brotli compression to reduce the size of transferred data, improving load times.
• SSL/TLS Optimization: Ensure your CDN is configured to handle SSL/TLS efficiently, as secure connections can impact performance.

‍

8. Monitor Continuous Performance

‍

Testing shouldn’t be a one-time task. Continually monitor your website’s performance using the tools mentioned. Regular checks help identify and fix issues promptly, ensuring your website remains fast and reliable.

‍

• Automated Monitoring: Set up alerts for significant performance drops. Tools like Pingdom or Uptime Robot can notify you if your website’s performance degrades.
• Regular Reports: Generate regular performance reports to track trends and identify potential issues before they affect user experience.

‍

9. User Feedback

‍

Finally, user feedback is invaluable. Encourage users to report any performance issues they encounter. Their insights can often highlight problems that automated tools might miss.

‍