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

Bloomerang - Bloomerang is a simple donor database and fundraising software solution that helps nonprofits decrease donor attrition and increase revenue.

Xapian - Xapian is an open source probabilistic information retrieval library, released under the GNU...

DonorPerfect - Nonprofits use DonorPerfect Fundraising Software for their Donor Management, Grant & Gift Tracking, Moves Management, Mass Mailing needs and more.

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.

Qgiv - Qgiv offers web based fundraising solutions for nonprofit organizations.