The technology disclosed applies data loss prevention (DLP) to those cloud-applications for which no application-specific parser is available. Known cloud applications can be arranged in categories of services such as “personal pages and blog,” “news websites,” “cloud-based storage services,” and “social media services.” A category includes a list of uniform resource locators (URLs) of providers of cloud applications that allow users to perform similar activities. The various providers in a category use different syntaxes to implement services in the category. The disclosed category-directed parsers synthesize interaction syntax patterns of a sample of providers in the category. A category-directed parser collects metadata from known cloud applications using multiple category-directed match rules synthesized from syntaxes used by the sample providers in the category. The metadata collected by the category-directed parser enables the DLP processor to focus analysis of the content being conveyed via a corresponding API.