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
ElasticSearch - Elasticsearch is an open source, distributed, RESTful search engine.
Tagalys - Data driven online Merchandising for eCommerce product listing pages.
Klevu - Klevu offers instant site search solution for eCommerce stores.
Certona - Certona is a multi-channel personalization platform for brands and retailers.