Before diving into configuration, it is crucial to understand what caching is and why it is so powerful for a GitHub Pages website. Caching is the process of storing copies of files in temporary locations, called caches, so they can be accessed much faster. For a web server, this happens at two primary levels: the edge cache and the browser cache.
The edge cache is stored on Cloudflare's global network of servers. When a visitor from London requests your site, Cloudflare serves the cached files from its London data center instead of fetching them from the GitHub origin server, which might be in the United States. This dramatically reduces latency. The browser cache, on the other hand, is stored on the visitor's own computer. Once their browser has downloaded your CSS file, it can reuse that local copy for subsequent page loads instead of asking the server for it again. A well-configured site tells both the edge and the browser how long to hold onto these files, striking a balance between speed and the ability to update your content.
The cornerstone of Cloudflare performance is found in the Caching app within your dashboard. The Browser Cache TTL and Edge Cache TTL settings determine how long files are stored in the visitor's browser and on Cloudflare's network, respectively. For a static site where content does not change with every page load, you can set aggressive values here.
Navigate to the Caching section in your Cloudflare dashboard. For Edge Cache TTL, a value of one month is a strong starting point for a static site. This tells Cloudflare to hold onto your files for 30 days before checking the origin (GitHub) for an update. This is safe for your site's images, CSS, and JavaScript because when you do update your site, Cloudflare offers a simple "Purge Cache" function to instantly clear everything. For Browser Cache TTL, a value of one hour to one day is often sufficient. This ensures returning visitors get a fast experience while still being able to receive minor updates, like a CSS tweak, within a reasonable timeframe without having to do a full cache purge.
Another critical setting is Caching Level. This option controls how much of your URL Cloudflare considers when looking for a cached copy. For most sites, the "Standard" setting is ideal. However, if you use query strings for tracking (e.g., `?utm_source=newsletter`) that do not change the page content, you should set this to "Ignore query string". This prevents Cloudflare from storing multiple, identical copies of the same page just because the tracking parameter is different, thereby increasing your cache hit ratio and efficiency.
While global cache settings are powerful, Page Rules allow you to apply hyper-specific caching behavior to different sections of your site. This is where you can fine-tune performance for different types of content, ensuring everything is cached as efficiently as possible.
Access the Page Rules section from your Cloudflare dashboard. A highly effective first rule is to cache your entire HTML structure. Create a new rule with the pattern `yourdomain.com/*`. Then, add a setting called "Cache Level" and set it to "Cache Everything". This is a more aggressive rule than the standard setting and instructs Cloudflare to cache even your HTML pages, which it sometimes treats cautiously by default. For a static site where HTML pages do not change per user, this is perfectly safe and provides a massive speed boost. Combine this with a "Edge Cache TTL" setting within the same rule to set a specific duration, such as 4 hours for your HTML, allowing you to push updates within a predictable timeframe.
You should create another rule for your static assets. Use a pattern like `yourdomain.com/assets/*` or `*.yourdomain.com/images/*`. For this rule, you can set the "Browser Cache TTL" to a much longer period, such as one month. This tells visitors' browsers to hold onto your stylesheets, scripts, and images for a very long time, making repeat visits incredibly fast. You can purge this cache selectively whenever you update your site's design or assets.
Compression reduces the size of your text-based files before they are sent over the network, leading to faster download times. While Gzip has been the standard for years, Brotli is a modern compression algorithm developed by Google that typically provides 15-20% better compression ratios.
In the Speed app within your Cloudflare dashboard, find the "Optimization" section. Here you will find the "Brotli" setting. Ensure this is turned on. Once enabled, Cloudflare will automatically compress your HTML, CSS, and JavaScript files using Brotli for any browser that supports it, which includes all modern browsers. For older browsers that do not support Brotli, Cloudflare will seamlessly fall back to Gzip compression. This is a zero-effort setting that provides a free and automatic performance upgrade for the vast majority of your visitors, reducing their bandwidth usage and speeding up your page rendering.
Images are often the largest files on a webpage and the biggest bottleneck for loading speed. Manually optimizing every image can be a tedious process. Cloudflare Polish is an automated image optimization tool that works seamlessly as part of their CDN, and it is a game-changer for content creators.
You can find Polish in the Speed app under the "Optimization" section. It offers two main modes: "Lossless" and "Lossy". Lossless Polish removes metadata and optimizes the image encoding without reducing visual quality. This is a safe choice for photographers or designers who require pixel-perfect accuracy. For most blogs and websites, "Lossy" Polish is the recommended option. It applies more aggressive compression, significantly reducing file size with a minimal, often imperceptible, impact on visual quality. The bandwidth savings can be enormous, often cutting image file sizes by 30-50%. Polish works automatically on every image request that passes through Cloudflare, so you do not need to modify your existing image URLs or upload new versions.
After implementing these changes, it is essential to measure the impact. Cloudflare provides its own analytics, but you should also use external tools to get a real-world view of your performance from around the globe.
Inside Cloudflare, the Analytics dashboard will show you a noticeable increase in your cached vs. uncached request ratio. A high cache ratio (e.g., over 90%) indicates that most of your traffic is being served efficiently from the edge. You will also see a corresponding increase in your "Bandwidth Saved" metric. To see the direct impact on user experience, use tools like Google PageSpeed Insights, GTmetrix, or WebPageTest. Run tests before and after your configuration changes. You should see significant improvements in metrics like Largest Contentful Paint (LCP) and Cumulative Layout Shift (CLS), which are part of Google's Core Web Vitals and directly influence your search ranking.
Performance optimization is not a one-time task but an ongoing process. As you add new types of content or new features to your site, revisit your caching rules and compression settings. With Cloudflare handling the heavy lifting, you can maintain a blisteringly fast website that delights your readers and ranks well in search results, all while running on the simple and reliable foundation of GitHub Pages.
A fast website is a secure website. Speed and security go hand-in-hand. Now that your site is optimized for performance, the next step is to lock it down. Our following guide will explore how Cloudflare's security features can protect your GitHub Pages site from threats and abuse.