The ENVRI Reference Model (ENVRI RM) and its ontological representation Open Information Linking for Environmental RIs (OIL-E) allow architects and engineers to describe the architecture and operational behavior of environmental and earth science research infrastructures (RIs) in a standardized way using community-agreed terminology. RI descriptions can be published as linked data, allowing discovery, querying and comparison using established Semantic Web technologies. The ENVRI Knowledge Base is a community knowledge base which uses OIL-E to capture information about environmental and earth science RIs in the ENVRI community for query and comparison. Such Knowledge-as-a-Service supports identifying the technologies and standards used for particular activities and services and evaluating research infrastructure subsystems and behaviors against certain criteria, such as compliance with the FAIR data principles.