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.
Nosto - Personalized shopping experiences for e-commerce businesses
Hawk Search - Site-search engine for eCommerce platforms.
Reflektion - Reflektion provides a predictive analytics platform that is easily deployable solutions for retailers and brands.
SearchSpring - SearchSpring is an eCommerce site search tool.
Nextopia - eCommerce Site Search & Navigation