An apparatus in one embodiment comprises a cloud-based web object indexing platform configured to communicate with multiple web servers over at least one network. The cloud-based web object indexing platform comprises a plurality of indexing applications having respective machine learning engines, with a given one of the indexing applications being configured to receive web objects over the network from one or more of the web servers and to process the received web objects utilizing its corresponding machine learning engine. The given indexing application is further configured to generate semantic information for association with particular ones of the web objects based at least in part on processing results provided by the corresponding machine learning engine. The semantic information is made accessible by the cloud-based web object indexing platform in association with the particular web objects over the network, for example, to a search engine or data analytics engine.