What kind of data caching mechanism can be implemented for the Front-End in case there is a downtime from Prismic?
Prismic is stable, your repository data is safe therefore there’s no real need to have a caching mechanism. But if you want or need, you can backup all of your content stored on your Prismic repository by querying all of the documents exposed by the API. Note that this will not fetch drafts, archived documents, custom types, or assets not linked to a document.
This process is described here: Query all your documents
Yes, we don’t recommend using a caching system as this can cause issues when the master ref is changed on every document update, this can cause websites to break.
Make sure you are using your CDN endpoint to offer your website extra protection and speed, for example https://your-repo-name.cdn.prismic.io/api/v2.
Also like Paulina said the platform is very stable. We have exceeded the Uptime of 99.9% for the past 26 consecutive months and are committed to maintaining this standard.