GSA (Google Search Appliance) Search API
YaCy provides exactly the same result output as the Google Search Appliance provides in XML format. This is an implementation of the Google Search Protocol Reference Version 6.8: XML Output service which Google provides to their commercial boxes that are rented in thousands all over the world to index intranets and company data in closed networks as well for universities etc.
Everyone who is using the Google XML API can instantly migrate to YaCy by just using the servlet at /gsa/searchresult within YaCy, i.e.
The result is computed by Solr; in fact this result is just an instance of the standard Solr select api /solr/select using a special Solr result writer for the GSA. The Google API was implemented as a Solr result writer.
If you are not forced to, then please do not use the GSA API since it is bad. Not the implementation is bad, the specification is bad. The result has no facets and you are forced to use XML which is bad if you have the opportunity to use i.e. json. We recommend to use the yjson result writer within the solr API which gives you full access to facets and a simple, standards-compliant (uses the opensearch specification for naming of properties) result set.