MongoDB is a source-available cross-platform document-oriented database program. Classified as a NoSQL database program, MongoDB uses JSON-like documents with optional schemas.

Apache Kafka is an open-source distributed streaming system used for stream processing, real-time data pipelines, and data integration at scale.

Elasticsearch is a distributed, RESTful search and analytics engine capable of addressing a growing number of use cases.

Redis is an open source (BSD licensed), in-memory data structure store, used as a database, cache, and message broker.