searchcode - A source code search engine
Algolia - Algolia's Search API makes it easy to deliver a great search experience in your apps & websites. Algolia Search provides hosted full-text, numerical, faceted and geolocalized search.
Apache Solr - Solr is an open source enterprise search server based on Lucene search library, with XML/HTTP and...
The Search - The all in one search engine for PH, DN, HN and GitHub ✊
ElasticSearch - Elasticsearch is an open source, distributed, RESTful search engine.
Autocomplete API - Optimize your search with suggested search query values