In this article 8
A slow website needs diagnosis before a redesign or hosting upgrade. Measure the same page on mobile and desktop, then separate server delays from download and browser work. These seven checks help you choose the next action.
1. Oversized images
Serve images sized for their displayed area and choose suitable compression. Avoid delaying the main image in the first viewport. Images further down the page can use lazy loading.
2. Slow server responses
When the browser waits for HTML, inspect application errors and resource usage. Changing hosting without measuring the bottleneck can leave the original problem unresolved.
3. Incorrect caching
Check whether static files download again on every visit. Choose cache rules by content type. Keep private accounts and shopping carts out of shared caches, then test these workflows after changes.
4. Heavy JavaScript and CSS
Identify unused scripts and styles. Defer optional work carefully and retest menus, forms and checkout. Applying the same loading rule to every script can break required features.
5. Distance between visitors and files
Base CDN decisions on audience location and observed delays. A CDN does not automatically repair slow application queries.
6. Repeated database work
If search, filters or dashboards are slow, investigate repeated reads and slow queries. Validate query and index changes in a test environment before comparing the real workflow.
7. Unnecessary plugins and external tools
Record the purpose of each plugin, chat widget and tracking script. Remove duplication one change at a time, checking that enquiry forms and analytics still work.
How to validate the result
Compare the same URL and device under similar network conditions. Use real visitor data when available alongside laboratory tests. Review loading, responsiveness and visual stability together.
See Google's LCP, INP and CLS guides. For diagnosis and an implementation plan, explore our website technical support.
