BigchainDB

vs

Redis

PouchDB is a free and open-source JavaScript database inspired by Apache CouchDB. The database is designed from the ground-up to run well within modern web browsers. With PouchDB you can create web applications that works as well offline as they do online. PouchDB achives this by storing data locally, then synchronize it with CouchDB and compatible servers when the user get internet access once again. This is especially useful for applications facing countries and regions with lower quality internet connections or unstable infrastructure.

OrbitDB is free and open-source serverless, distributed, peer-to-peer database for IPFS (Internet Planetary File System). The database is most commonly used for decentralized apps (dApps) and blockchain applications. With OrbitDB, IPFS is used for data storage, while IPFS Pubsub is used to automatically sync databases with peers across the network. Which makes OrbitDB an "eventually consistent database" that uses CRDTs for conflict-free database merges, suited for decentralization of data.

RxDB is short for Reactive Database and is a NoSQL-database for JavaScript Applications like Websites, hybrid Apps, Electron-Apps, Progressive Web Apps and NodeJs. Reactive means that you can not only query the current state, but subscribe to all state changes like the result of a query or even a single field of a document. This is great for UI-based realtime applications in way that makes it easy to develop and also has great performance benefits. To replicate data between your clients and server, RxDB provides modules for realtime replication with any CouchDB compliant endpoint and also with custom GraphQL endpoints.

Memcached is a free and open-source in-memory key-value store used for storing small chunks of data objects in dynamic memory. Most commonly, Memcached is used to speed up dynamic database-driven websites by caching data and objects in RAM to reduce the number of times an data sources needs to be fetched. Rather than querying the database for each unique request, Memcached can be used to store data from common pages in memory and speedup and improve the experience of a web application or website.

Apache Cassandra is a free and open-source, distributed, wide column store, NoSQL database management system. Apache Cassandra is designed to handle large amounts of data across many commodity servers, providing high availability with no single point of failure. The database has become the choice of many organizations that need scalability and high availability without compromising performance. Apache Cassandra also provides support for replicating across multiple datacenters, providing lower latency for end users of Cassandra-powered applications.

MongoDB is an open-source document-oriented distributed database built for modern applications. MongoDB uses JSON-like documents with optional schemas and is classified as a NoSQL database. The database is freely distributed under the Server Side Public License, but MongoDB provides commercial version of the database for enterprise-scale applications.