Most of the time your front end doesn’t talk directly with Elasticsearch or Solr: there’s a search API layer in the middle.
This search-API builds any sort of Elasticsearch or Solr query, it may contain very complex business logic.
We call it Black Box Search API: because RRE-Enterprise doesn’t need to know what are the implementation details of such middle layer nor the programming language involved, it just needs to know the REST endpoint to use to run the evaluation.
N.B. RRE-Enterprise supports REST Black Box Search API only
When configuring the target of your evaluation to be an external search engine you need to make sure you configure all the information RRE-Enterprise needs to talk with such search engine instance.
With this approach, you can point directly to your custom Black Box Search API!