Understand Every Type of Cache, Why It Matters, and How It Can Break Your Site
Understanding how caching works (and when it works against you) is critical to maintaining a fast, reliable, and accurate website.
We’ll break down the major WordPress cache types your site relies on, show you how to clear each one, and help you spot the exact symptoms when caching is to blame so your site updates actually show up.
If you’ve ever updated something on your site and didn’t see it reflect right away-or visitors complained of broken or outdated pages-there’s a good chance caching was the culprit.
Let’s take a closer look at what each cache stores, when it can cause issues, and how to properly clear it.
1. WordPress Cache and How It Works
Caching is how WordPress speeds up your site by saving a copy of what it built the first time—so it doesn’t have to rebuild it every time someone visits. When a user lands on a page for the first time, WordPress pulls data from the database using PHP and combines it into a complete HTML page.
That process takes server power and time. If WordPress had to do that for every visitor, every time, your site would crawl.
Instead, caching stores a ready-made version of that page—what’s called a static HTML file—in a fast-access layer. The next time someone visits, WordPress simply serves that prebuilt page from cache.
The result? Faster load times and reduced server strain. But because these pages are saved versions, they won’t reflect changes you’ve made until the cache is cleared.
Knowing what’s cached, when it breaks, and how to clear it ensures your content stays fresh while keeping your site lightning fast.
2. How to Spot a Caching Problem
Not sure if caching is the culprit? Here are a few common signs:
You update a page or product, but it still shows the old version
Users report seeing broken layouts or outdated prices
One browser shows the update, but another doesn’t
Logged-out users see different content than logged-in users
If any of these sound familiar, it’s likely a cache needs clearing.
3. The Most Common WordPress Cache Types
Here’s a breakdown of the key caching layers you should understand:
🧠 Browser Cache
Stores: CSS, JS, fonts, images
Breaks When: Visitors don’t see your latest design or content updates
How to Clear: Ask users to do a hard refresh (
CTRL+SHIFT+R
) or manually clear their browser cache via Browser > Settings > Privacy > Clear Browsing Data
🗂️ Page Cache
Stores: Fully rendered HTML of your site
Breaks When: You make changes but users still see the old version
How to Clear: Use a plugin (e.g., WP Rocket > Dashboard > Clear Cache) or your hosting panel
If your host uses server-level caching, use the tools below to clear your cache directly from their dashboard.
How to Clear Page Cache by Host (with Step-by-Step Links):
SiteGround > Site Tools > Speed > Caching
WP Engine > WP Engine > Caching > Clear All Caches
Kinsta > MyKinsta > Sites > Tools > Clear Cache
Bluehost > Bluehost > Settings > Performance > Clear Cache
GoDaddy > Manage WordPress > Settings > Flush Cache
Cloudways > Application Management > Application Settings > Clear Cache
🌐 CDN Cache
Stores: Static assets (CSS, JS, images) on global edge servers
Breaks When: Users in different locations see different versions of your site
How to Clear: Log into your CDN provider dashboard (e.g., Cloudflare > Caching > Configuration > Purge Everything)
🧮 Object Cache
Stores: Repeated database queries in memory
Breaks When: Products, forms, or dynamic content don’t update
How to Clear: Use your plugin or hosting dashboard (e.g., WP Rocket > Database > Clear Object Cache, or server-side tools like Redis CLI > redis-cli flushall)
⚙️ OPcache
Stores: Compiled PHP code
Breaks When: Code changes don’t take effect
How to Clear: Hosting control panel (e.g., cPanel > PHP Selector > Options > Clear OPcache) or restart PHP
🛒 WooCommerce Cache
Stores: Cart fragments, prices, session data
Breaks When: Prices are wrong, cart doesn’t update, or checkout fails
How to Clear: WooCommerce > Status > Tools > Clear WooCommerce Transients. Optionally, disable cart fragments using plugins like Perfmatters or WooCommerce Booster
🧭 Edge Full Page Cache
Stores: Fully rendered HTML pages on CDN edge servers
Why It Matters: Improves performance globally by reducing latency
Breaks When: Changes are made on the server but users get cached HTML
How to Clear: Use your CDN dashboard (e.g., Cloudflare APO > Caching > Purge Everything)
4. How These Caches Work Together
In most modern WordPress setups, multiple caching layers are working at once:
A visitor’s browser saves files
Your CDN serves static assets from the nearest server
Your server serves a cached page
Your database uses object caching for fast queries
Your PHP is precompiled with OPcache
A change in one layer may require clearing multiple cache types to fully reflect across the stack.
5. Tools to Help You Test and Manage Cache
These tools help you identify if caching is causing display issues or slowdowns:
GTmetrix – Great for checking what’s cached and detecting CDN usage
WebPageTest.org – Shows TTFB (Time To First Byte), useful for diagnosing server or edge caching issues
Cloudflare Cache Analytics – If using Cloudflare, see real cache hit/miss data
Query Monitor (plugin) – Diagnoses object cache and slow queries
Browser Developer Tools – Every modern browser (like Chrome, Firefox, Edge, Safari) includes built-in developer tools. You can right-click any page, choose “Inspect,” and view asset headers under the “Network” tab to check cache status (look for `cache-control`, `expires`, or `status: 304`)
6. Cache Best Practices & Prevention Tips
Don’t panic: Caching is a feature, not a flaw-learn to control it
Use a staging site when making major changes so cache doesn’t interfere
Configure your caching plugin to automatically purge cache on content updates
Exclude dynamic pages (cart, checkout, login) from caching
Educate your team so they don’t mistake a cached issue for a broken site
7. How to Safely Clear Cache Without Breaking Things
Clearing cache can fix bugs, but doing it recklessly may temporarily slow your site or break compatibility. Here’s a safe approach:
Clear cache on your plugin or hosting panel first.
Purge CDN cache if using Cloudflare or similar.
Flush OPcache if you’ve made code changes.
Clear object cache and transients (especially for WooCommerce).
Ask users to hard refresh their browser or test in incognito mode.
8. Table: Cache Types at a Glance 📋
Cache Type | What It Stores | Breaks When... | How to Clear |
---|---|---|---|
🧠Browser Cache ⓘ | CSS, JavaScript, Images | Styles/images not updating | Hard refresh or clear browser cache |
🗂️Page Cache ⓘ | Full HTML pages | Site content not reflecting updates | Use hosting panel or caching plugin |
🌐CDN Cache ⓘ | Static assets (CSS, JS, images) | Different users see outdated content | Purge cache in CDN dashboard |
🧮Object Cache ⓘ | Database query results | Dynamic content like products are stale | Flush via plugin or server memory tools |
⚙️OPcache ⓘ | Compiled PHP scripts | PHP edits don’t apply | Restart PHP or flush OPcache |
🛒WooCommerce Cache ⓘ | Cart fragments, pricing, transients | Cart, checkout, or pricing bugs | Use Woo tools + performance plugin |
Conclusion
Understanding caching is essential for maintaining a fast, reliable WordPress site in 2025. Don’t just clear your cache blindly-know which layer you’re dealing with and why. Use the chart above as a go-to troubleshooting reference whenever content doesn’t update properly.
FAQs
Q: What’s the difference between object cache and page cache?
Page cache stores fully rendered pages, while object cache stores database query results.
Q: Do I need a caching plugin if my host provides caching?
Not always, but plugins can give you more control over specific caching layers.
Q: How often should I clear cache?
Only when content changes or issues arise. Frequent clearing can reduce performance benefits.