Dynamic Yield - Personalization & customer experience management
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.
Optimizely - A/B testing you'll actually use.
ElasticSearch - Elasticsearch is an open source, distributed, RESTful search engine.
AB Tasty - AB Tasty is an all-inclusive platform for conversion rate optimization, personalization, customer activation, and testing.
Klevu - Klevu offers instant site search solution for eCommerce stores.