Cache Warmup is a NitroPack service that schedules new optimizations for pages after they get purged or invalidated.

The purge or invalidate can happen manually (after you manually purge/invalidate cached pages) or automatically (using Automatic Cache Clear). In all cases, Cache Warmup schedules new optimizations for the cleaned pages.

Here is what it looks like while Cache Warmup is working:

Use the Pause button to pause the current warmup process.

The Start button forces a new warmup for all enabled pages in the Warmup configuration.

In the General Settings panel, notice the Cache Warmup setting:

Use the toggle button on the right to enable or disable Cache Warmup for your store.

The Configure button opens up a popup to additionally configure Cache Warmup. Here is what it looks like:

Let's dive into the details.

These toggles configure the page versions Cache Warmup should schedule for each of your pages. By default, Cache Warmup always schedules an optimization for the default language and currency, which is why they cannot be disabled.

Example:
If we enable GBP and EUR, then Cache Warmup would schedule optimizations for:

The above means that each of your pages has 4 versions, each version requiring a separate optimization

The settings here control which pages should Cache Warmup schedule only in the following cases:

Note: The toggles under Pages do not control how Cache Warmup behaves when you purge/invalidate a specific URL or route. Remember, when Cache Warmup is enabled from the toggle in the General Settings panel, it schedules an optimization for any purged/invalidated URL.

With the Fine-Tune option Include category paths in product URLs, you instruct a fresh cache warmup to also include category paths in the product URLs. For example:

https://your-store-url.com/index.php?route=product/product&path=20_21&product_id=60

Without the Fine-Tune option, Cache Warmup only handles product URLs, such as:
​https://your-store-url.com/index.php?route=product/product&product_id=60

Cache warmup creates its own sitemap based on the selected types of pages you want to warm up.

Important Note: The Warmup Sitemap cannot currently include pages defined in the NitroPack Custom Page Types.

Any change you make to your Cache Warmup settings affects the estimated optimizations for your pages. Here is how it looks:

For the particular case, when you are using the Journal2 / Journal3 theme, the Cache Warmup estimate can be affected by the Journal Popup module or the Journal Header Notice module. If you see a very high warmup estimate, consider disabling some of your Journal Popup or Journal Header Notice modules.