If you use one of Full Page Cache Extensions, then it’s extremely necessary to add a Magento Cache Warmer / Crawler to your e-commerce store. Such extension will crawl your site to ensure that all the pages provide the fastest load time. Warmers and Crawlers also refresh old cached pages. As a result, your visitors get the most relevant content and the fastest speed. This type of Magento extensions often relies on special techniques designed to reduce bandwidth and CPU usage.
Cache Warmers / Crawlers are also used to improve cache hit rate of a website – the ratio of cached and uncached requests. Sites with the higher hit rate are always faster (combined with a fast cache solution, of course). The Full Page Cache Crawlers / Warmers solve this by pre-caching uncached site pages. As a result you get more cached and less uncached requests, which increases the cache hit rate.
Cache Warmer / Crawler by ExtendWare
This extension will efficiently crawl your e-commerce store in search of uncached pages and newer versions of already cached pages. Additionaly, pages, your users can not access, won’t be crawled. Cache Warmer / Crawler by ExtendWare can also filter out generated URLs by URL type and regular expression. The extension uses multiple crawler threads to reduce the total crawl time. It also reduces CPU and bandwidth usage. The extension costs $99.
Brim’s Full Page Cache Warmer
This module also crawls categories, products, and CMS pages to prime the page cache automatically. As a results visitors get the newest copies of cached pages as fast as possible. Brim’s Full Page Cache Warmer is designed to supplement Full Page Cache Magento extension by Brim, but it can be used with any other full page cache module as well. With this extension you will be able to limit crawling by different types of pages, and set a crawling frequency and concurrency. Brim’s Full Page Cache Warmer includes shell crawler, and supports multi-store installation. The extension costs $69.
Magento Free Full Page Cache Crawler by maverick193
This module allows you to take control over the pages you want to warm. By installing it on your Magento e-commerce shop you can choose which pages to crawl, when the extension should do it, and how. You can perform all the procedures manually from the backend or shell. There is also possibility to warm everything automatically via cronjob. Magento Full Page Cache Crawler Magento extension is free. Hit the below link for the additional information.