istSOS is an OGC SOS server implementation written in Python. istSOS allows for managing and dispatch observations from monitoring sensors according to the Sensor Observation Service standard.

swe4citizenscience is an open citizen observatories repository on GitHub, to be used to develop best practices on how to use OGC specifications for citizen observatories. Specifically, the COBWEB project has developed an ontology called Sensor Web Enablement for Citizen Science (SWE4CS), which will be proposed as a best practice document for citizen science at OGC.

This could also be a base for an INSPIRE best practice (or TG) for Citizen Science Data Sharing.

Developed by OGC this is a web-server, tomcat application that provides an endpoint that accepts GML resoponses from WFS GetFeature requests. There are limitations if you want to test more than 500 polygons (crashed the service)

smart.finder SDI (formerly known as "terraCatalog") offers a powerful and scalable metainformation system based on open standards.

Features:

deegree is open source software for spatial data infrastructures and the geospatial web. deegree offers components for geospatial data management, including data access, visualization, discovery and security. Open standards are at the heart of deegree.

It comes with an INSPIRE workspace to help to provide the network services as required by INSPIRE

MapServer is an Open Source geographic data rendering engine. Beyond browsing GIS data, MapServer allows you create “geographic image maps”, that is, maps that can direct users to content.

GeoServer is an open source software server written in Java for sharing and editing geospatial data.