Website performance optimization services
in New York

A familiar complaint after any website update: the change is saved, the editor can see it, and customers still see the old version. Usually nothing is broken. One of several caches is doing exactly what it was told to do.

Caching makes sites fast by storing a finished answer and handing it out again instead of rebuilding it. The trouble is that a typical site has several caches stacked on top of each other, each with its own rules for when to forget.

The browser is the first layer. It keeps images, stylesheets and scripts so that the next page loads quickly. If those files keep the same name after a change, the browser may keep using its old copy for days. Adding a version marker to file names whenever they change solves this cleanly. Stale files are the usual culprit.

A content delivery network is the next layer. It stores copies of pages and files on servers close to visitors. It is fast and cheap, but a changed page stays stale until its stored copy expires or someone purges it. A purge takes seconds.

The server often has a page cache of its own, keeping complete HTML so the application does not run for every visit. Plugins and platforms manage this in different ways. Some clear the right pages automatically after an edit, others clear nothing, and some clear everything.

Deeper inside sit object and query caches, which remember database results. They rarely cause visible problems, but when they do, the symptoms are strange, such as prices that update on one page and not on another.

Good caching starts with a map. For each layer, the team should know what it stores, how long it keeps it, and how to clear it. That map belongs in the documentation, not in the memory of one developer.

Expiry times should match how often content changes. A logo can be cached for a year. A stock level or a price should be cached briefly or not at all. Mixing both on one page requires deliberate separation.

Purging should be precise. Clearing everything after each small edit wastes the benefit of caching and slows the site for everyone. Clearing the exact pages affected keeps it fast and current.

Some pages must never be cached. Logged in users and shopping carts usually need to bypass the page cache completely. Otherwise one customer may briefly see the account details or basket of another, which is a serious problem.