HyperDex!

MongoDB (from "humongous") is a scalable, high-performance, open source NoSQL database. The database is document-oriented so it manages collections of JSON-like documents. Many applications can thus model data in a more natural way, as data can be nested in complex hierarchies and still be query-able and indexable.

RethinkDB pushes JSON to your apps in realtime.

Cockroach is a distributed key/value datastore which supports ACID transactional semantics and versioned values as first-class features. The primary design goal is global consistency and survivability, hence the name. Cockroach aims to tolerate disk, machine, rack, and even datacenter failures with minimal latency disruption and no manual intervention. Cockroach nodes are symmetric; a design goal is one binary with minimal configuration and no required auxiliary services.

Free & open source, high-performance, distributed memory object caching system, generic in nature, but intended for use in speeding up dynamic web applications by alleviating database load.

Azure DocumentDB is a NoSQL document database service designed from the ground up to natively support JSON and JavaScript directly inside the database engine. It’s the right solution for web and mobile applications when predictable throughput, low latency, and flexible query are key. Microsoft consumer applications like OneNote already use DocumentDB in production to support millions of users.

Titan is a scalable graph database optimized for storing and querying graphs containing hundreds of billions of vertices and edges distributed across a multi-machine cluster. Titan is a transactional database that can support thousands of concurrent users executing complex graph traversals in real time.

Apache Ignite In-Memory Data Fabric is a high-performance, integrated and distributed in-memory platform for computing and transacting on large-scale data sets in real-time, orders of magnitude faster than possible with traditional disk-based or flash technologies.Apache Ignite In-Memory Data Fabric is designed to deliver uncompromised performance for a wide set of in-memory computing use cases from high performance computing, to the industry most advanced data grid, highly available service grid, and streaming. »

Cachelot works within a fixed amount of memory. No garbage collector. Small metadata, near perfect memory utilization (overhead is 5-7% of the total memory).Smooth responsiveness, without any "gaps" for both read and write operations. Most operations have O(1) complexity.Can be used as a library or as a stand-alone memcached server.

XCache is a fast, stable PHP opcode cacher that has been tested and is now running on production servers under high load. It is tested on Linux and FreeBSD and supported under Windows, for thread-safe and non-thread-safe versions of PHP. This relatively new opcode caching software has been developed by mOo, one of the developers of Lighttpd, to overcome some of the limitations of the existing solutions at that time; such as being able to use it with new PHP versions as they arrive.

The APC (Alternative PHP Cache) is an Open Source opcode cache extension to the PHP programming language server daemon.

XAP is an in-memory computing software platform that processes all your data & applications in real time.