Cache Warmup
Updated over a week ago

What it does & How it works

The cache warmup system has two primary functions:

  1. Keeping the site optimized when automated cache purges happen

  2. Preemptively optimizing all pages found in a configured URL source.

The warmup system prepares optimized versions of your pages without having to wait for organic traffic. This is great because it helps you prepare your pages for visitors without relying on organic traffic.

For optimal results, the system needs a source of links for your site. You can choose the Standard method, which will use your homepage URL to identify popular pages or a sitemap XML.

Important Note: The option to provide a sitemap XML is available only for users on paid plans.

If a sitemap is configured, it will take precedence. Otherwise, only the links found on your homepage will be warmed up.

If you donโ€™t define a source, the system will warm up only URLs purged via automated events (for example, after editing a post, changing the price of a product, etc.).

When the Standard mode is chosen, or a sitemap is configured, you should click on the "Update" button to start the warmup process.

Once you click the button, the system estimates how many optimizations will be used in the process. After the estimate is done, the warmup process will start automatically.

The warmup system prepares optimized versions for desktop and mobile devices.

Additionally, when Variation cookies with known values are configured, the system will prepare optimized versions of all possible combinations of the cookies and their known values. This ensures great coverage of possible organic requests resulting in a much better cache hit ratio after the warmup is complete.

Further information for this feature implementation per platform can be found in the following articles:

Possible errors

In case NitroPack faces an issue accessing your website or Sitemap URL, you will be notified of this in our Dashboard.

Below is a list of the possible errors that you may encounter. ๐Ÿ‘‡

Unexpected error

This error message can be seen for various reasons, and we suggest reaching out to our Support team to dig deeper by using the chat bubble in the bottom right corner of this page.

Invalid sitemap format

This usually indicates that you have added a non-XML sitemap in the Cache Warmup settings.

For NitroPack to be able to crawl a sitemap, it should be formatted as an XML file without any errors present.

Error 403 (NitroPack cannot access your sitemap)

This error message usually indicates that NitroPack has faced a 403 Forbidden error when trying to access your website's sitemap.

To resolve this, we recommend that you whitelist NitroPack's IP addresses:




You should also double-check your server settings and ensure that the file is publicly accessible.

Error 404 (Sitemap not found)

Essentially, NitroPack encountered a 404 Not Found error when accessing your website's sitemap.

This usually means that the file itself does not exist or is not publicly available.

To solve this, we recommend making sure that the file is publicly accessible or re-uploading your sitemap with the correct URL.

๐Ÿ“Œ If you need any assistance or have questions, you can always reach out to our support team at [email protected] or by using the chat bubble located in the bottom right corner of this page.

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