All Prerendering engine results are cached by default. Cache TTL can be changed in the Prerendering settings, individually per each host.
Caching allows to offload servers, save bandwidth and speed up sequential requests to the same pages by web crawlers, mean better SEO score for your website.
We do not charge for requests to the cached results, mean cheaper Prerendering service for you.
Cache TTL can be set per each host individually starting from 2 hours and ending with 744 hours (31 days).
The cache may be fully purged once per 2 hours, but the specific page can be purged individually at any moment. Read more in cache purging docs.