Some embodiments provide systems and methods for sandboxing content optimization to occur entirely within a network edge or PoP of a CDN. Some embodiments pass a first request for a first URL to a first back-end at the network edge that is configured to cache an optimized instance of the particular object. When the optimized instance of the particular object is not cached at the first back-end, a second request is issued for a second URL identifying a non-optimized instance of the particular object. The second request resolves internally within the network edge to a second back-end that is configured to cache the non-optimized object. The non-optimized object from the second back-end is optimized and passed to the first back-end. The first back-end caches the optimized instance of the non-optimized object and serves the optimized instance to a requesting end user.