CDN vs Cache: What’s the Difference for WordPress?
Understand how caching and content delivery networks overlap and why neither term describes one single technology.
Short answer: A CDN distributes content across edge locations; caching stores reusable content. CDNs commonly use caching, but a cache does not have to be a CDN and a CDN does more than simply “turn caching on.”
A geographically distributed edge can reduce network distance for cacheable resources.
Origin cache
A geographically distributed edge can reduce network distance for cacheable resources.
Dynamic HTML may be cached differently from static assets.
- Identify which layer is caching the response.
- Prefer the narrowest safe purge instead of clearing every cache by default.
- Verify behavior while logged out or in a private browsing session when testing public page caching.
Browser cache
Dynamic HTML may be cached differently from static assets.
When troubleshooting, inspect whether the stale or slow response came from WordPress, the host, the CDN or the browser.
- Identify which layer is caching the response.
- Prefer the narrowest safe purge instead of clearing every cache by default.
- Verify behavior while logged out or in a private browsing session when testing public page caching.
CDN edge cache
When troubleshooting, inspect whether the stale or slow response came from WordPress, the host, the CDN or the browser.
A geographically distributed edge can reduce network distance for cacheable resources.
- Identify which layer is caching the response.
- Prefer the narrowest safe purge instead of clearing every cache by default.
- Verify behavior while logged out or in a private browsing session when testing public page caching.
Cache keys and purges
A geographically distributed edge can reduce network distance for cacheable resources.
Dynamic HTML may be cached differently from static assets.
- Identify which layer is caching the response.
- Prefer the narrowest safe purge instead of clearing every cache by default.
- Verify behavior while logged out or in a private browsing session when testing public page caching.
When a CDN helps most
Dynamic HTML may be cached differently from static assets.
When troubleshooting, inspect whether the stale or slow response came from WordPress, the host, the CDN or the browser.
- Change one important variable at a time.
- Compare repeatable behavior rather than one isolated score.
- Keep reliability and maintainability ahead of marginal benchmark gains.
Practical decision rule
Fix the layer the evidence points to. Caching helps repeated server work; CSS and JavaScript work affect rendering and responsiveness; images and fonts affect transfer and discovery; hosting and application behavior affect origin response. Avoid solving a different problem just because a tool is popular.
Related guides
Sources and further reading
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