MongoDB - MongoDB (from "humongous") is a scalable, high-performance NoSQL database.
MkDocs - Project documentation with Markdown.
PostgreSQL - PostgreSQL is a powerful, open source object-relational database system.
GitBook - Modern Publishing, Simply taking your books from ideas to finished, polished books.
ElasticSearch - Elasticsearch is an open source, distributed, RESTful search engine.
Docusaurus - Easy to maintain open source documentation websites