Amazon CloudSearch is a fully-managed search service that allows users to build search applications without having to manage any infrastructure. It automatically scales to support large data and traffic volumes. Users can build search applications in less than an hour and pay only for what they use on a pay-as-you-go basis with no upfront costs or commitments. CloudSearch supports both structured and unstructured data and provides features like faceting, range searching, fielded searching, and customizable relevance ranking.