WordPress Cache Detector Tool

What is the WordPress Cache Detector Tool?

The WordPress Cache Detector Tool is a free online utility that helps you understand how your website handles caching and performance at the HTTP level. Instead of guessing whether your pages are cached, served through a CDN, or sending the right Cache-Control headers, you can paste a URL and get an instant, human-readable report. This is especially useful for WordPress site owners, SEO specialists, performance engineers, and hosting providers who want to verify that page caching and asset caching are configured correctly.

Under the hood, the tool sends a request with the dedicated User-Agent BugWP-Cache-Detector/1.0, measures time-to-first-byte (TTFB), inspects key response headers, detects common CDNs, and looks for signs of WordPress cache plugins and server-level caching. It also samples a small set of static assets (such as CSS, JavaScript and images) and reads their cache lifetimes so you can see how long browsers and CDNs are allowed to store those files.

Why cache detection matters for WordPress performance and SEO

Caching is one of the most effective ways to speed up a WordPress website. Without caching, every page view has to be generated dynamically: PHP runs, the database is queried, and templates are rendered on the fly. That process adds latency, increases server load, and makes your site more vulnerable to traffic spikes. When page caching is enabled, most visitors receive a pre-generated HTML copy from a cache layer instead of triggering the full WordPress stack every time.

Search engines like Google care deeply about speed and user experience. Metrics such as time-to-first-byte, Largest Contentful Paint (LCP), and overall Core Web Vitals are influenced by how well caching is configured. If your origin server is slow, your CDN is not caching HTML, or your assets have very short lifetimes, your site can feel sluggish even on good connections. The WordPress Cache Detector Tool surfaces these issues in a simple report, so you can see what is happening in real traffic instead of relying on assumptions or outdated screenshots.

How the WordPress Cache Detector Tool works

When you enter a URL into the WordPress Cache Detector Tool, the backend first normalises it. If you type example.com without a scheme, the tool will automatically test with HTTPS by default, while making sure that local or private URLs such as localhost or 127.0.0.1 are rejected for safety. It then sends a GET request using the BugWP-Cache-Detector/1.0 User-Agent, follows redirects, and measures TTFB for the final response.

Once the response is received, the tool inspects the Content-Type header to determine whether the page is likely HTML. If it is, the response body is parsed for WordPress-specific markers such as wp-content, wp-includes, wp-json links, and optional pingback URLs. That allows the tool to identify whether the site is WordPress-based, even when the X-Powered-By header is hidden.

The tool then looks at cache-related headers. It reads Cache-Control and extracts values like max-age and s-maxage, calculating an approximate TTL in seconds. If there is no usable directive, the tool reports that the cache lifetime is not specified. It also inspects common CDN and reverse-proxy headers such as CF-Cache-Status, X-Cache, and X-Proxy-Cache, which indicate whether the response was a cache HIT or MISS at the edge.

Sampling static files and TTL information

Beyond the HTML itself, the WordPress Cache Detector Tool goes a step further by sampling a subset of static assets directly referenced in the page. It scans the HTML for common elements such as <link rel="stylesheet">, <script src="…"> and <img src="…" />, and then resolves those URLs relative to the page. To be polite and avoid unnecessary load, only a limited number of same-origin assets are tested.

Each sampled asset is then inspected via a lightweight HEAD or GET request. The tool collects the HTTP status code, the asset-level Cache-Control header, and derives a TTL in seconds. It also checks whether the asset appears to be served via a CDN or directly from the origin. In the interface, you see a concise table of file names, their type (CSS, JS, image or static), the cache lifetime expressed in seconds, minutes, hours or days, and whether the request was served by a CDN or the origin server.

In the UI, all file names in the “Sampled static files & TTL” table are clickable. Clicking a file opens it in a new tab, which is very useful if you want to verify minification, file size, or confirm that you are looking at the correct version. A small copy button lets you copy the list of sampled asset URLs in one click, which is handy when you need to share diagnostic information with a developer or hosting provider.

Understanding the cache quality and tooltips

The WordPress Cache Detector Tool summarises your configuration with a simple cache quality badge. This badge takes into account whether an edge cache HIT was detected, whether meaningful Cache-Control headers are present, and whether the configured TTL is reasonable. A “good” rating usually means the response was served from a CDN or reverse-proxy cache, and that the page and assets are allowed to live in cache for a sensible amount of time. An “ok” rating indicates partial caching, while “poor” means that no useful caching appears to be in place or the TTL is extremely short.

To avoid cluttering the interface with too much technical text, detailed hints are moved into small tooltips. For example, the TTFB card includes a tooltip explaining that a target below 200 ms is ideal, 200–600 ms is acceptable, and values above 600 ms are generally slow. Another tooltip describes how the approximate TTL is calculated from the Cache-Control header and what it means when the TTL is “Not specified”. CDN-related information such as cf-cache-status: DYNAMIC is summarised and surfaced through a contextual tooltip so that the UI stays clean but power users can still access the raw signals.

WordPress cache plugin detection also comes with a tooltip that reflects the detection confidence. If a specific plugin is identified via response headers or HTML comments, the tool can state that the detection confidence is high. If only indirect hints are present, it may mark the confidence as medium or low. This makes it easier to know when you can trust the plugin name that appears in the report.

Using the tool to improve Core Web Vitals and SEO

The report generated by the WordPress Cache Detector Tool always includes a short list of suggested next steps. These suggestions are built from the actual data returned by your site: missing Cache-Control headers, short TTL values, lack of CDN usage, high TTFB, or the absence of any recognisable WordPress cache solution. Instead of generic advice, you get specific tips like increasing the TTL of certain static assets, enabling full-page caching, or putting your site behind a robust CDN.

By following these recommendations and observing the results over time, you can materially improve your Core Web Vitals scores. Cached HTML and long-lived static assets reduce server load and latency, which in turn helps LCP and overall responsiveness. Search engines reward sites that feel fast and stable, so tuning your caching configuration with the help of this tool can indirectly contribute to better rankings and higher conversion rates.

Handling blocked requests and whitelisting the User-Agent

In some cases, security rules, WAFs or CDN configurations may block the WordPress Cache Detector Tool. If your host or firewall returns HTTP status codes like 403, 429 or a challenge-style 503, the tool identifies that the request appears to be blocked or rate-limited rather than serving real page content. When this happens, a small popup explains that your site is likely blocking the diagnostic User-Agent and suggests whitelisting it.

The User-Agent used by the tool is BugWP-Cache-Detector/1.0. If you control your own firewall, WAF, or CDN rules, you can allow requests from that User-Agent so the tool can test your site properly. This does not bypass normal security for regular visitors; it simply allows a lightweight diagnostic request that helps you understand and improve your caching configuration. Once whitelisted, you can re-run the test and see a complete cache report instead of an error or protection page.

Who should use the WordPress Cache Detector Tool?

This tool is designed for anyone responsible for the health and performance of a WordPress website. If you are a site owner, it gives you a quick way to verify whether your hosting provider truly configured caching the way they claim. If you are an SEO specialist, it lets you confirm that your performance work is backed by real HTTP headers and proper TTLs. If you are a developer or performance engineer, it offers a repeatable way to check that cache rules are behaving as expected after deployments and configuration changes.

Because the interface is intentionally simple, non-technical users can understand the gist (cached vs. not cached, CDN vs. origin, good vs. poor cache quality), while technical users can drill down into per-file TTLs, raw headers and diagnostic hints. The copy buttons make it easy to share full header dumps or sampled asset lists with collaborators, making this tool a practical part of your optimization workflow.

Whether you are launching a new project, migrating to a new host, or debugging a Core Web Vitals warning in Google Search Console, the WordPress Cache Detector Tool gives you a clear, honest view of how your cache is actually behaving in the wild, and what you can improve next.