Cassandra Alternatives

MongoDB (from "humongous") is a scalable, high-performance, open source NoSQL database.

open-source

Redis is an open source in-memory data structure project implementing a distributed, in-memory key-value database with optional durability.

A distributed open-source database with a flexible data model for documents, graphs, and key-values.

The world's most popular open source database

OrientDB - The World's First Distributed Multi-Model NoSQL Database with a Graph Database Engine.

PostgreSQL is a powerful, open source object-relational database system.

The open-source database for the realtime web

Document-Oriented NoSQL Database

Meet Neo4j: The graph database platform powering today's mission-critical enterprise applications, including artificial intelligence, fraud detection and recommendations.

A scalable JSON document database for web, mobile, IoT and serverless applications.

Amazon DynamoDB is a fast and flexible NoSQL database service for all applications that need consistent, single-digit millisecond latency at any scale. It is a fully managed cloud database and supports both document and key-value store models.

HTTP + JSON document database with Map Reduce views and peer-based replication