SearchBlox is described as 'Out-of-the-box Enterprise Search Solution built on top of Apache Lucene/Solr. It is fast to deploy, easy to manage and available for both on-premise and cloud deployment' and is a site search engine in the development category. There are more than 25 alternatives to SearchBlox for a variety of platforms, including Linux, Web-based, Self-Hosted, Mac and Windows apps. The best SearchBlox alternative is Algolia. It's not free, so if you're looking for a free alternative, you could try Algolia or Elasticsearch. Other great apps like SearchBlox are Apache Solr, Manticore search, Searchspring and Pagefind.
Expertrec Search is an easy alternative to searchblox. It is also built on lucene and it comes with great default configurations. With searchblox, one gets a better search engine than going with Solr directly. Same with Expertrec.