Website performance: where to start

Published 6 October 2026 · CANSEO editorial

Review images, scripts, and layout movement before adding more software to a slow website.

Test representative pages

Choose a homepage, a content page, and a page with the most important interaction. Test mobile conditions as well as desktop. A single fast page does not describe the experience across the site.

Separate a one-time laboratory test from data about real visits. Results can vary with device, network, location, caching, and server load. Record the URL, conditions, and date so later comparisons have context.

Inspect images first

Large photographs are a common source of unnecessary download size. Resize images to a sensible display size, compress them, and choose an appropriate format. Retain enough quality for the image’s purpose.

Reserve image dimensions to reduce movement as the page loads. Load below-the-fold images when needed, but be careful about delaying a primary image that visitors need immediately.

Review scripts and embeds

List third-party scripts and ask what each contributes. Multiple analytics systems, chat widgets, and embedded videos can add work for the browser. Remove unused integrations and check whether a lighter approach can support the same visitor task.

A performance score is not the visitor’s objective. Make sure a form, menu, or tool still works after optimisation. A smaller download is useful only when it preserves the required experience.

Fix one issue and compare

Make a targeted change, repeat the same test conditions, and record the outcome. Avoid changing every component at once if you need to understand which edit helped. Keep backups so an unexpected regression can be reversed.

For detailed measurement, consult the Core Web Vitals documentation. Treat performance as ongoing maintenance whenever new images, scripts, or templates are introduced.