> For the complete documentation index, see [llms.txt](https://competitions.gitbook.io/competition-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://competitions.gitbook.io/competition-docs/performance/customer-cache.md). # Customer Cache Customer Cache serves pre-built HTML pages to authenticated users, this makes pages load in milliseconds rather than seconds. The challenge with caching logged-in users is dynamic content such as wallet balances, prize states, competition entries, and personalised popups that are unique to each customer.\ \ Customer Cache solves this with an AJAX fragment system: dynamic elements are updated seamlessly just after serving the cache. From the customer's perspective the page loads instantly and their dynamic data appears within a fraction of a second. Stale files are detected & regenerated in the background ensuring your customers always get a fast & updated experience. Customers who land on a page containing specific query strings such as `utm_source`, Klaviyo (`_kx`), or Facebook parameters will also receive the cached version of the page even if they're logged in, which will help when traffic surges due to promotions. {% hint style="success" %} Cache is cleared when a competition is updated or when a competition has ended {% endhint %}