draw.io - Online diagramming application
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.
LucidChart - LucidChart is the missing link in online productivity suites. LucidChart allows users to create, collaborate on, and publish attractive flowcharts and other diagrams from a web browser.
Google Custom Search - Google Custom Search enables you to create a search engine for your website, your blog, or a collection of websites.
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.
ElasticSearch - Elasticsearch is an open source, distributed, RESTful search engine.