S3View portal runs on the EO Cloud
The EOCloud platform (https://eocloud.cloudferro.com/) where the S3View processing chain is running hosts the whole archive of Sentinel-3 data (among other datasets) and retrieves NRT data within a few hours after acquisition.
It also provides the EO Finder service (https://finder.eocloud.eu), an interface and a webservice to explore the EO Data archive and find the files that correspond to a set of criteria.
S3View uses this service to detect the availability of new NRT data on EO Cloud platform and trigger the processing chain which produces the visualizations that can be seen in the S3View portal (usually 4 hours after acquisition).
You can find more information at https://www.oceandatalab.com/127f2700-975d-4967-a2bb-e3651d2f52a4
The S3View portal is available at https://s3view.oceandatalab.com