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CDN industry insights, technical deep-dives and benchmark reports
How Can Image-Heavy Websites Use CDN? How to Test Caching, Formats, and Loading Speed
Why is an image-heavy website still slow after being connected to a CDN? This article explains image cache duration, version updates, WebP and AVIF formats, responsive sizes, lazy loading, and above-the-fold image optimization, and provides testing methods for cache hit ratio, multi-region download speed, and LCP.
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How to Choose a CDN for Global Websites: Start with Speed Tests by User Country
When choosing a CDN for an overseas-facing website, global node count alone is not enough. This article explains how to plan speed tests around the countries, cities, carriers, and peak hours of real users, and how to compare CDNs using success rate, P50/P95, TTFB, cache hit ratio, origin traffic, and cost.
What Sites Are Free CDNs Good For? Check Quotas, Caching, and Usage Limits
What makes free CDNs so appealing isn't just that they cost nothing—it's that they come with almost no barrier to trying them out: point your domain, update your DNS records, and enable the proxy, and your site is up and running in no time. For personal blogs, portfolios, open-source project documentation, and small websites that have just launched, this can indeed be the most suitable starting point. But "free for now" and "zero long-term cost" are not the same thing.
How to Verify Alibaba Cloud CDN Is Working After Integration: Domain and Cache Check Steps
After you finish configuring Alibaba Cloud CDN, how do you confirm it is actually in effect? This article walks through domain status, CNAME resolution, live requests, X-Cache hit status, and multi-region speed tests, then troubleshoots issues such as a successful setup where caching still does not work, or where some regions continue to reach the origin server.
Website Fast on China Telecom but Slow on China Mobile: How Can You Tell If It's a CDN Issue?
Your site loads quickly over China Telecom but slowly over China Mobile — how do you troubleshoot it? This article examines CDN node scheduling, carrier lines, DNS, IPv4/IPv6, cache HIT/MISS, and origin fetch paths, and provides same-city comparison tests and fault diagnosis methods.
What Causes High TTFB? Should You Check the CDN or the Origin Server First?
If your site's TTFB is high, should you check the CDN or the origin server first? This article works through a layer-by-layer diagnosis — DNS, TCP, TLS, cache HIT/MISS, the origin fetch path, server applications, and databases — and provides curl tests, a comparison matrix, and optimization methods.
If your users are mainly in mainland China, which regions and carriers should you focus on when choosing a CDN?
If your users are mainly in mainland China, which regions and carriers should you test when choosing a CDN? This article explains the testing priorities for China Telecom, China Unicom, China Mobile, and key regions, and offers a method for selecting a CDN based on user distribution, business type, and P95 performance.
What to do when a CDN returns 502, 503, or 504? First identify whether the issue is with the edge node, origin fetch, or origin server.
What do 502, 503, or 504 errors mean when a website is served through a CDN? This article examines the common causes of each status code and uses response headers, origin bypass tests, curl timing, and server logs to determine whether the fault lies at the CDN node, in the origin fetch path, or at the origin server.
Ping Is Fast but Your Website Is Slow? Don't Confuse Latency with Load Speed
Domain ping latency is low, so why is the website still slow to load? This article explains the differences between ping, DNS, TCP, TLS, TTFB, download speed, and browser rendering, and covers troubleshooting methods using curl, browser developer tools, and multi-node speed tests.
Can’t detect a CDN—is none in use, or was it just not identified?
A CDN check that returns no detection result does not necessarily mean the website is not using a CDN. This article looks at the common reasons a CDN goes undetected and walks through a step-by-step verification process using DNS records, response headers, multi-region testing, and back-end configuration.