An Open-Source XML Database-Based Implementation of the FDSN Station Webservice: exist-fdsn-station

Abstract The International Federation of Digital Seismograph Networks has established the fdsnws-station application programming interface (API) standard for read-only access to seismic station metadata, provided primarily in an extensible markup language (XML) format called StationXML. Here, we present an extension of the standard API that introduces controlled operations for interacting with the underlying metadata repository. The proposed interface is designed to support direct handling of StationXML documents within distributed service-oriented infrastructures. We implemented the extended API using a framework that provides a native XML database management system and an embedded application platform. This approach offers a design advantage because the schema-less database allows ingestion of metadata from heterogeneous sources while preserving the XML structure. The software implementation, exist-fdsn-station, is containerized and can be integrated as a reusable component within larger infrastructures. Performance tests show that the system scales predictably with the size of the returned data and can support large aggregated metadata collections. The software is currently used in operational environments at the Istituto Nazionale di Geofisica e Vulcanologia (INGV) data center, including the public fdsnws-station endpoint.