1. A system for refreshing cached content, comprising: an application/presentation layer coupled to a content management system, wherein the application/presentation layer is configured to: generate page content based on a plurality of content objects retrieved from the content management system; determine a plurality of content identifiers based on the plurality of content objects, wherein each of the plurality of content identifiers corresponds to a respective one of the plurality of content objects; and insert an invalidation header including the plurality of content identifiers into the generated page content; a caching layer operatively coupled to the application/presentation layer, and configured to: receive the generated page content containing the invalidation header from the application/presentation layer; and update a map of content identifiers to generated pages, based on the invalidation header; wherein the content management system is configured to provide a content invalidation message to the caching layer in response to a content editor tool of the content management system updating a first object stored in the content management system, the content invalidation message including a first content identifier uniquely identifying the first content object, and wherein the caching layer is configured to, upon receiving the content invalidation message, determine one or more cached pages that are invalid based on the included first content identifier, based on the map of content identifiers to generated pages.