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.
Price2Spy - Price2Spy is a price monitoring, pricing analytics, and repricing tool, meant to help eCommerce professionals keep an eye on their competitors or retailers.
ElasticSearch - Elasticsearch is an open source, distributed, RESTful search engine.
Skuuudle - Discover, match and monitor your eCommerce competitors.
Site Search 360 - Site Search 360 enhances and improves your built-in CMS or product search with autocompletion, semantic search, filters, facets, detailed analytics, and a whole lot of customization options.
Prisync - Prisync is a competitor price tracking and monitoring software for all sizes of e-commerce companies worldwide.