Work on paid search engine

Algolia works on developing and maintaining a search engine through its Search & Discovery API, which is a paid service used by over 9,000 companies.

Epsilon works on an AI search engine specifically for scientific research, which includes paid features such as professional and organization plans with unlimited searches and other premium services.

Landeed provides a property title search service, which is a specialized search engine for property-related documents. It offers both free and paid services, meeting the criteria of a paid search engine. However, it is not a general-purpose search engine but rather a niche service focused on real estate documents.

Baidu provides a search engine service and offers advertising services through Baidu Marketing, which includes paid features.

Trieve works on developing a search engine with features like full-text search, semantic vector search, and hybrid search. They offer various pricing plans, including a free tier and paid options, which indicates the presence of paid features.

Promoted.ai offers a unified ads server and search engine SDK for marketplaces, which indicates they work on developing and maintaining a search engine. Additionally, the search engine includes paid features as it is designed to optimize ads and increase revenue for online marketplaces.

Exa works on developing a search engine specifically designed for AI applications, which includes paid features beyond the free tier of 1000 requests per month.

Quivr offers a unified search engine across all documents, tools, and databases powered by AI, and provides paid plans including a Plus plan at $29 per seat per month and an Enterprise plan with custom pricing.

DuckDuckGo works on developing and maintaining a search engine that includes paid features through private ads and subscription fees for Privacy Pro.