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.

Lucidworks Fusion - Lucidworks’ advanced search platform, provides the enterprise-grade capabilities needed to design, develop and deploy intelligent search apps at scale.

Google Custom Search - Google Custom Search enables you to create a search engine for your website, your blog, or a collection of websites.

ElasticSearch - Elasticsearch is an open source, distributed, RESTful search engine.

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.

Coveo - Enterprise search technology for better customer support, customer self-service, and knowledge management in the digital workplace.