What is the Dynamic Rendering recommendation?

The Dynamic rendering recommendation proposed by Google describes how to make any websites based on JavaScript crawlable by Google and any other bots. It defines a simpler protocol than the now deprecated Crawling scheme specification between bots and HTTP servers. This protocol allows bots to retrieve HTML snapshots instead of the HTML pages sent to regular users which requires JavaScript to be properly rendered.

You can find more information about how Dynamic Rendering works here.