Systems and methods for improved performance in the storing and retrieving of objects. In one embodiment, the invention comprises a multi-tiered caching system implemented in a network transformation proxy. The proxy performs transformations on Web content received from a Web server and stores the transformed content in the caching system. The lowest tier of caches stores the content as cache objects, while higher tiers store references to lower tiers (such as the tier which stores the objects) as their cache objects. Cache entries are looked up using a plurality of keys. Each of the keys is used to look up an entry in a different tier of the cache.