The decision was made after the owners recognized that they have a common objective - helping people in the UK (and beyond) understand web hosting and all its intricacies, including NoSQL databases. This list is updated monthly. Learn more here.

In April 2020, NoSQL-Database.org joined forces with HostingData.co.uk. These two websites and the teams responsible for their creation will now work together.

Finally, if digital privacy is your concern, make sure to check out the best VPN services , as well as the best free VPNs around.

The original intention has been. The movement began early 2009 and is growing rapidly. Often more characteristics apply such as:(not ACID), aand more. So the misleading term "nosql" (the community now translates it mostly with "") should be seen as an alias to something like the definition above.

[based on 7 sources, 15 constructive feedback emails (thanks!) and 1 disliking comment. Agree / Disagree? Tell us so! By the way: this is a strong definition and it is out there here since 2009!]

some of the points:

NOSQL DEFINITION: Next Generation Database Management Systems mostly addressing some of the points: being non-relational, distributed, open-source and horizontally scalable.

Core NOSQL Systems: [Mostly originated out of a Web 2.0 need]

Wide Column Store / Column Families

Hadoop / HBase API: Java / any writer, Protocol: any write call, Query Method: MapReduce Java / any exec, Replication: HDFS Replication, Written in: Java, Concurrency: ?, Misc: Links: 3 Books [1, 2, 3], Guru99 Article >>

MapR, Hortonworks, Cloudera Hadoop Distributions and professional services.

Cassandra massively scalable, partitioned row store, masterless architecture, linear scale performance, no single points of failure, read/write support across multiple data centers & cloud availability zones. API / Query Method: CQL and Thrift, replication: peer-to-peer, written in: Java, Concurrency: tunable consistency, Misc: built-in data compression, MapReduce support, primary/secondary indexes, security features. Links: Documentation, PlanetC*, Company.

Scylla Cassandra-compatible column store, with consistent low latency and more transactions per second. Designed with a thread-per-core model to maximize performance on modern multicore hardware. Predictable scaling. No garbage collection pauses, and faster compaction.

Hypertable API: Thrift (Java, PHP, Perl, Python, Ruby, etc.), Protocol: Thrift, Query Method: HQL, native Thrift API, Replication: HDFS Replication, Concurrency: MVCC, Consistency Model: Fully consistent Misc: High performance C++ implementation of Google's Bigtable. » Commercial support

Accumulo Accumulo is based on BigTable and is built on top of Hadoop, Zookeeper, and Thrift. It features improvements on the BigTable design in the form of cell-based access control, improved compression, and a server-side programming mechanism that can modify key/value pairs at various points in the data management process.

Amazon SimpleDB Misc: not open source / part of AWS, Book (will be outperformed by DynamoDB!)

Cloudata Google's Big table clone like HBase. » Article

MonetDB Column Store pioneer since 2002.

HPCC from LexisNexis, info, article

Apache Flink (formerly known as Stratosphere) massively parallel & flexible data analytics platform, API: Java, Scala, Query Method: expressive data flows (extended M/R, rich UDFs, iteration support), Data Store: independent (e.g., HDFS, S3, MongoDB), Written in: Java, License: Apache License V2.0, Misc: good integration with Hadoop stack (HDFS, YARN), source code on Github

IBM Informix horizontally and vertically scalable, relational, partitioned row store, document store API / Query Method: SQL (native, DRDA, JDBC, ODBC), MongoDB wire listener, mixed mode, replication: master / slave, peer-to-peer, sharding, grid operations, written in: C, Concurrency: row, page, table, db locking, Misc: ACID, built-in data compression, scheduler, automatic cyclic storage management, extensible, in memory acceleration, native ports from ARM v6 up Links: Documentation, IIUG, Company.

Splice Machine Splice Machine is an RDBMS built on Hadoop, HBase and Derby. Scale real-time applications using commodity hardware without application rewrites, Features: ACID transactions, ANSI SQL support, ODBC/JDBC, distributed computing

eXtremeDB Financial Edition massively scalable in-memory and persistent storage DBMS for analytics on market data (and other time series data). APIs: C/C++, Java Native Interface (JNI), C#/.NET), Python, SQL (native, ODBC, JDBC), Data layout: row, columnar, hybrid, Written in: C, Replication: master/slave, cluster, sharding, Concurrency: Optimistic (MVCC) and pessimistic (locking)

ConcourseDB a distributed self-tuning DBMS with automatic indexing, version control and ACID transactions. Written In: Java. API/Protocol: Thrift (many languages). Concurrency: serializable transactions with just-in-time locking. Misc: uses a buffered storage system to commit all data to disk immediately while perform rich indexing in the background.

Druid open-source analytics data store for business intelligence (OLAP) queries on event data. Low latency (real-time) data ingestion, flexible data exploration, fast data aggregation. Scaled to trillions of events & petabytes. Most commonly used to power user-facing analytic applications. API: JSON over HTTP, APIs: Python, R, Javascript, Node, Clojure, Ruby, Typescript + support SQL queries Written in: Java License: Apache 2.0 Replication: Master/Slave

KUDU Apache Kudu (incubating) completes Hadoop's storage layer to enable fast analytics on fast data.

Elassandra Elassandra is a fork of Elasticsearch modified to run on top of Apache Cassandra in a scalable and resilient peer-to-peer architecture. Elasticsearch code is embedded in Cassandra nodes providing advanced search features on Cassandra tables and Cassandra serve as an Elasticsearch data and configuration store.

[OpenNeptune, Qbase, KDI]

Document Store

Oracle NoSQL Database can be configured securely with the proper technical guides. Network communications between NoSQL clients, utilities, and NoSQL server components can and should be encrypted. This original document is curated and maintained by Will Ellis. He has additional guides on his website about the best VPNs.

Elastic API: REST and many languages, Protocol: REST, Query Method: via JSON, Replication + Sharding: automatic and configurable, written in: Java, Misc: schema mapping, multi tenancy with arbitrary indexes, » Company and Support, » Article

ArangoDB, FaunaDB, OrientDB, gunDB (Doc Store & GraphDB & Key-Value. More details in Category Multimodel DBMS)

MongoDB API: BSON, Protocol: C, Query Method: dynamic object-based language & MapReduce, Replication: Master Slave & Auto-Sharding, Written in: C++,Concurrency: Update in Place. Misc: Indexing, GridFS, Freeware + Commercial License Links: » Talk, » Notes, » Company

Cloud Datastore A fully managed Document store with multi-master replication across data centers. Originally part of Google App Engine, it also has REST and gRPC APIs. Now Firestore?!

Azure DocumentDB is a fully managed, globally distributed NoSQL DBMS perfect for the massive scale and low latency needs of modern applications. Guarantees: 99.99% availability, 99% of reads at <10ms and 99% of writes at <15ms. Scale to handle 10s-100s of millions of requests/sec and replicate globally with the click of a button. APIs: .NET, .NET Core, Java, Node.js, Python, REST. Query: SQL. Links: » Service, » Pricing, » Playground, » Documentation

RethinkDB API: protobuf-based, Query Method: unified chainable query language (incl. JOINs, sub-queries, MapReduce, GroupedMapReduce); Replication: Sync and Async Master Slave with per-table acknowledgements, Sharding: guided range-based, Written in: C++, Concurrency: MVCC. Misc: log-structured storage engine with concurrent incremental garbage compactor

Couchbase Server API: Memcached API+protocol (binary and ASCII) , most languages, Protocol: Memcached REST interface for cluster conf + management, Written in: C/C++ + Erlang (clustering), Replication: Peer to Peer, fully consistent, Misc: Transparent topology changes during operation, provides memcached-compatible caching buckets, commercially supported version available, Links: » Wiki, » Article

ToroDB API: MongoDB API and SQL, Protocol: MongoDB Wire Protocol / MongoDB compatible, Query Method: dynamic object-based language & SQL, Replication: RDBMS Backends' Replication System & Support for replication from MongoDB's Replica Set, Written in: Java, Concurrency: MVCC. Misc: Open Source NoSQL and SQL DBMS. The agileness of a doc DB with the reliability and the native SQL capabilities of PostgreSQL. Links: » Company

SequoiaDB API: BSON, Protocol: C, Query Method: dynamic object-based language, Replication: Master Slave & Auto-Sharding, Written in: C++, Misc: Indexing, Large Object Store, Transaction, Free + Commercial License, Benchmark, Code

NosDB a 100% native .NET Open Source NoSQL Document DBMS (Apache 2.0 License). It also supports SQL querying over JSON Documents. Data can also be accessed through LINQ & ADO.NET. NosDB also provides strong server-side and client-side caching features by integrating NCache.

RavenDB RavenDB is an Open Source NoSQL DBMS. Multi-Model: Document, Key-Value, Graph, Distributed Counters, Attachments. Fully Transactional (ACID) across database and throughout the cluster. Multiplatform: C#, Node.js, Java, Python, Ruby, Go. Multisystem: Windows, Linux, Mac OS, Docker, Raspberry Pi. Native GUI, MapReduce, full text search, memory management.

UnQlite UnQLite is an embedded NoSQL (Key/Value store and Document-store) DBMS. Similar to MongoDB, Redis, CouchDB etc. as well a standard Key/Value store similar to BerkeleyDB, LevelDB, etc. It's a in-process software library which implements a self-contained, serverless, zero-configuration, transactional NoSQL DBMS. Open source, distributed under the 2-Clause BSD license.

MarkLogic Server (developer+commercial) API: JSON, XML, Java Protocols: HTTP, REST Query Method: Full Text Search and Structured Query, XPath, XQuery, Range, Geospatial, Bitemporal Written in: C++ Concurrency: Shared-nothing cluster, MVCC Misc: Petabyte-scalable and elastic (on premise in the cloud), ACID + XA transactions, auto-sharding, failover, master slave replication (clusters), replication (within cluster), high availability, disaster recovery, full and incremental backups, government grade security at the doc level, developer community »

Clusterpoint Server (freeware+commercial) API: XML, PHP, Java, .NET Protocols: HTTP, REST, native TCP/IP Query Method: full text search, XML, range and Xpath queries; Written in C++ Concurrency: ACID-compliant, transactional, multi-master cluster Misc: Petabyte-scalable document store and full text search engine. Information ranking. Replication. Cloudable.

JSON ODM Object Document Mapper for JSON-Documents written in pure JavaScript. It queries the collections with a gremlin-like DSL that uses MongoDB's API methods, but also provides joining. The collections extend the native array objects, which gives the overall ODM a good performance. Queries 500.000 elements in less then a second.

NeDB NoSQL DBMS for Node.js in pure javascript. It implements the most commonly used subset of MongoDB's API and is quite fast (about 25,000 reads/s on a 10,000 documents collection with indexing).

Terrastore API: Java & http, Protocol: http, Language: Java, Querying: Range queries, Predicates, Replication: Partitioned with consistent hashing, Consistency: Per-record strict consistency, Misc: Based on Terracotta

AmisaDB: Architected to unify the best of search engine, NoSQL and NewSQL DB technologies. API: REST and many languages. Query method: SQL. Written in C++. Concurrency: MVCC. Misc: ACID transactions, data distribution via consistent hashing, static and dynamic schema support, in-memory processing. Freeware + Commercial License

JasDB Lightweight open source document DBMS written in Java for high performance, runs in-memory, supports Android. API: JSON, Java Query Method: REST OData Style Query language, Java fluent Query API Concurrency: Atomic document writes Indexes: eventually consistent indexes

RaptorDB JSON based, Document store DBMS with compiled .net map functions and automatic hybrid bitmap indexing and LINQ query filters

djondb jonDB API: BSON, Protocol: C++, Query Method: dynamic queries and map/reduce, Drivers: Java, C++, PHP Misc: ACID compliant, Full shell console over google v8 engine, djondb requirements are submitted by users, not market. License: GPL and commercial

EJDB Embeddable JSON DBMS engine. API: C/C++, Protocol: Native, HTTP, Websockets Written in: C11, Query language: XPath like query language (JQL), Concurrency: RW locking, Misc: Single file database, Indexing, License: MIT

densodb DensoDB is a new NoSQL document DBMS. Written for .Net environment in c# language. It’s simple, fast and reliable. Source

SisoDB A Document Store on top of SQL-Server.

SDB For small online databases, PHP / JSON interface, implemented in PHP.

NoSQL embedded db Node.js asynchronous NoSQL embedded DBMS for small websites or projects. DBMS supports: insert, update, remove, drop and supports views (create, drop, read). Written in JavaScript, no dependencies, implements small concurrency model.

ThruDB (please help provide more facts!) Uses Apache Thrift to integrate multiple backend DBMS as BerkeleyDB, Disk, MySQL, S3.

iBoxDB Transactional embedded DBMS, it can embed into mobile, desktop and web applications, supports on-disk and in-memory storages. API: Java,C# (Android, Mono, Xamarin, Unity3D). Query Method: SQL-like and KeyValue. Written In: Java, C#. Replication: MasterSlave, MasterMaster.

BergDB API: Java/.NET. Written in: Java. Replication: Master/Slave. License: AGLP. Historical queries. ACID. Schemaless. Concurrency: STM and persistent data structure. Append-only storage. Encrypted storage. Flexible durability control. Secondary & composite indexes. Transparently serializes Java/.NET objects.

ReasonDB 100% JavaScript automatically synchronizing multi-model DBMS with a SQL like syntax (JOQULAR) and swappable persistence stores. It supports joins, nested matches, projections or live object result sets, asynchronous cursors, streaming analytics, 18 built-in predicates, in-line predicates, predicate extensibility, indexable computed values, fully indexed Dates and Arrays, built in statistical sampling. Persistence engines include files, Redis, LocalStorage, block storage, and more.

IBM Cloudant Cloud based, open-source, zero-config. Based on CouchDB and BigCouch.

BagriDB API: XQJ/XDM, REST, OpenAPI, Protocols: Java, HTTP, Query Method: distributed XQuery + server-side XQuery/Java extensions, Written in: Java, Concurrency: MVCC, Document format: XML, JSON, POJO, Avro, Protobuf, etc. Misc: in-memory Data and Computation Grid, transparent replication and fail-over, true horizontal scalability, ACID transactions, rich indexeng and trigger capabilities, pluggable persistent store, pluggable data formats. GitHub

Key Value / Tuple Store

DynamoDB Automatic ultra scalable NoSQL DB based on fast SSDs. Multiple Availability Zones. Elastic MapReduce Integration. Backup to S3 and much more...

Azure Table Storage Collections of free form entities (row key, partition key, timestamp). Blob and Queue Storage available, 3 times redundant. Accessible via REST or ATOM.

Riak API: tons of languages, JSON, Protocol: REST, Query Method: MapReduce term matching , Scaling: Multiple Masters; Written in: Erlang, Concurrency: eventually consistent (stronger then MVCC via Vector Clocks)

Redis API: Tons of languages, Written in: C, Concurrency: in memory and saves asynchronous disk after a defined time. Append only mode available. Different kinds of fsync policies. Replication: Master / Slave, Misc: also lists, sets, sorted sets, hashes, queues. Cheat-Sheet: », great slides » Admin UI » From the Ground up »

LevelDB Fast & Batch updates. DB from Google. Written in C++. Blog », hot Benchmark », Article » (in German). Java access. C# (for Universal Windows Platform) access.

RocksDB API: C++. Written in C++. Facebook`s improvements to Google`s LevelDB to speed throughput for datasets larger than RAM. Embedded solution.

Berkeley DB API: Many languages, Written in: C, Replication: Master / Slave, Concurrency: MVCC, License: Sleepycat, Berkeley DB Java Edition: API: Java, Written in: Java, Replication: Master / Slave, Concurrency: serializable transaction isolation, License: Sleepycat

Helium API: C, C++, Java, Python, NodeJS. Written in C. Key-value store aimed at high throughput and low latency (usecs) applications. Designed to run on many-core systems with fast storage such as SSDs and NVMs. Low and predictable memory footprint, low write amplification. License: proprietary Mode: embedded, single serverLinks Multi million ops/sec on GCP, Real-time low latency KV with Helium and Samsung Z-SSD

KeyDB API: Multiple languages (Redis Compatible) Replication: Master / Master - A multithreaded fork of Redis with a ton of extra features such as Active Replication, AWS S3 integration, and significantly lower latency.

GenieDB Immediate consistency sharded KV store with an eventually consistent AP store bringing eventual consistency issues down to the theoretical minimum. It features efficient record coalescing. GenieDB speaks SQL and co-exists / do intertable joins with SQL RDBMs.

BangDB API: Get,Put,Delete, Protocol: Native, HTTP, Flavor: Embedded, Network, Elastic Cache, Replication: P2P based Network Overlay, Written in: C++, Concurrency: ?, Misc: robust, crash proof, Elastic, throw machines to scale linearly, Btree/Ehash

Chordless API: Java & simple RPC to vals, Protocol: internal, Query Method: M/R inside value objects, Scaling: every node is master for its slice of namespace, Written in: Java, Concurrency: serializable transaction isolation,

Scalaris (please help provide more facts!) Written in: Erlang, Replication: Strong consistency over replicas, Concurrency: non blocking Paxos.

Scalien API / Protocol: http (text, html, JSON), C, C++, Python, Java, Ruby, PHP,Perl. Concurrency: Paxos.

Voldemort Open-Source implementation of Amazons Dynamo Key-Value Store.

Dynomite Open-Source implementation of Amazons Dynamo Key-Value Store. written in Erlang. With "data partitioning, versioning, and read repair, and user-provided storage engines provide persistence and query processing".

KAI Open Source Amazon Dynamo implementation, Misc: slides

MemcacheDB API: Memcache protocol (get, set, add, replace, etc.), Written in: C, Data Model: Blob, Misc: Is Memcached writing to BerkleyDB.

Faircom C-Tree API: C, C++, C#, Java, PHP, Perl, Written in: C,C++. Misc: Transaction logging. Client/server. Embedded. SQL wrapper (not core). Been around since 1979.

LSM Key-Value DBMS that was written as part of SQLite4, They claim it is faster then LevelDB. Instead of supporting custom comparators, they have a recommended data encoding for keys that allows various data types to be sorted.

KitaroDB : A fast, efficient on-disk data store for Windows Phone 8, Windows RT, Win32 (x86 & x64) and .NET. Provides for key-value and multiple segmented key access. APIs for C#, VB, C++, C and HTML5/JavaScript. Written in pure C for high performance and low footprint. Supports async and synchronous operations with 2GB max record size.

upscaledb : (embedded solution) API: C, C++, .NET, Java, Erlang. Written in C,C++. Fast key/value store with a parameterized B+-tree. Keys are "typed" (i.e. 32bit integers, floats, variable length or fixed length binary data). Has built-in analytical functions like SUM, AVERAGE etc.

STSdb API: C#, Written in C#, embedded solution, generic XTable<TKey,TRecord> implementation, ACID transactions, snapshots, table versions, shared records, vertical data compression, custom compression, composite & custom primary keys, available backend file system layer, works over multiple volumes, petabyte scalability, LINQ.

Tarantool/Box API: C, Perl, PHP, Python, Java and Ruby. Written in: Objective C ,Protocol: asynchronous binary, memcached, text (Lua console). Data model: collections of dimensionless tuples, indexed using primary + secondary keys. Concurrency: lock-free in memory, consistent with disk (write ahead log). Replication: master/slave, configurable. Other: call Lua stored procedures.

Chronicle Map In-memory (opt. persistence via mmap), highly concurrent, low-latency key-value store. API: Java. Written in: Java. Protocol: in-process Java, remote via Chronicle Engine + Wire: binary, text, Java, C# bindnings. Concurrency: in-memory lock striping, read-write locks. Replication: multi-master, eventually consistent.

Maxtable API: C, Query Method: MQL, native API, Replication: DFS Replication, Consistency: strict consistency Written in: C.

Pincaster For geolocalized apps. Concurrency: in-memory with asynchronous disk writes. API: HTTP/JSON. Written in: C. License: BSD.

RaptorDB A pure key value store with optimized b+tree and murmur hashing. (In the near future it will be a JSON document DBMS much like mongodb and couchdb.)

TIBCO Active Spaces peer-to-peer distributed in-memory (with persistence) datagrid that implements and expands on the concept of the Tuple Space. Has SQL Queries and ACID (=> NewSQL).

allegro-C Key-Value concept. Variable number of keys per record. Multiple key values, Hierarchic records. Relationships. Diff. record types in same DB. Indexing: B*-Tree. All aspects configurable. Full scripting language. Multi-user ACID. Web interfaces (PHP, Perl, ActionScript) plus Windows client.

nessDB A fast key-value DBMS (using LSM-Tree storage engine), API: Redis protocol (SET,MSET,GET,MGET,DEL etc.), Written in: ANSI C

HyperDex Distributed searchable key-value store. Fast (latency & throughput), scalable, consistent, fault tolerance, using hyperspace hashing. APIs for C, C++ and Python.

SharedHashFile Fast, open source, shared memory (using memory mapped files e.g. in /dev/shm or on SSD), multi process, hash table, e.g. on an 8 core i7-3720QM CPU @ 2.60GHz using /dev/shm, 8 processes combined have a 12.2 million / 2.5 to 5.9 million TPS read/write using small binary keys to a hash file containing 50 million keys. Uses sharding internally to mitigate lock contention. Written in C.

Symas LMDB Ultra-fast, ultra-compact key-value embedded data store developed by Symas for the OpenLDAP Project. It uses memory-mapped files, so it has the read performance of a pure in-memory DBMS while still offering the persistence of standard disk-based DBMS, and is only limited to the size of the virtual address space, (it is not limited to the size of physical RAM)

Sophia Sophia is a modern embeddable key-value DBMS designed for a high load environment. It has unique architecture that was created as a result of research and rethinking of primary algorithmic constraints, associated with a getting popular Log-file based data structures, such as LSM-tree. Implemented as a small C-written, BSD-licensed library.

NCache .NET Open Source Distributed Cache. Written in C#. API .NET & Java. Query Parallel SQL Query, LINQ & Tags. Misc: Linear Scalability, High Availability, WAN Replication, GUI based Administration & Monitoring Tools, Messaging, Runtime Data Sharing, Cache & Item Level Events, Continuous Query & Custom Events, DB Dependencies & Expirations

TayzGrid Open Source In-Memory JCache compliant Data Grid. Written in Java. API Java, JCache JSR 107 & .NET. Query SQL & DB Synchronization. Misc: Linear Scalability, High Availability, WAN Replication, GUI based Administration & Monitoring Tools, Distributed Messaging, MapReduce, Entry Processor and Aggregator

PickleDB Redis inspired K/V store for Python object serialization.

LightCloud (based on Tokyo Tyrant)

Hibari Hibari is a highly available, strongly consistent, durable, distributed key-value data store

OpenLDAP Key-value store, B+tree. Lightning fast reads+fast bulk loads. Memory-mapped files for persistent storage with all the speed of an in-memory DBMS. No tuning conf required. Full ACID support. MVCC, readers run lockless. Tiny code, written in C, compiles to under 32KB of x86-64 object code. Modeled after the BerkeleyDB API for easy migration from Berkeley-based code. Benchmarks against LevelDB, Kyoto Cabinet, SQLite3, and BerkeleyDB are available, plus full paper and presentation slides.

Genomu High availability, concurrency-oriented event-based K/V DBMS with transactions and causal consistency. Protocol: MsgPack, API: Erlang, Elixir, Node.js. Written in: Elixir, Github-Repo.

BinaryRage BinaryRage is designed to be a lightweight ultra fast key/value store for .NET with no dependencies. Tested with more than 200,000 complex objects written to disk per second on a crappy laptop 🙂 No configuration, no strange driver/connector, no server, no setup - simply reference the dll and start using it in less than a minute.

Elliptics Github Page »

DBreeze Professional, open-source, NoSql (embedded Key/Value storage), transactional, ACID-compliant, multi-threaded, object DBMS management system for .NET 3.0> MONO. Written in C#.

TreodeDB API: Scala. Written in Scala. Replication: Replicas vote on writes and reads. Sharding: Hashes keys onto array of replica cohorts. Concurrency: Optimistic + Multiversion Concurrency Control. Provides multirow atomic writes. Exposes optimistic concurrency through API to support HTTP Etags. Embedded solution.

BoltDB Key/Value DB written in Go.

Serenity Serenity DBMS implements basic Redis commands and extends them with support of Consistent Cursors, ACID transactions, Stored procedures, etc. The DBMS is designed to store data bigger then available RAM.

Cachelot API: Memcached. Written in C++. In-memory LRU cache with very small memory footprint. Works within fixed amount of memory. Cachelot has a C++ cache library and stand-alone server on top of it.

filejson Use a JSON encoded file to automatically save a JavaScript value to disk whenever that value changes. A value can be a Javascript: string, number, boolean, null, object, or an array. The value can be structured in an array or an object to allow for more complex data stores. These structures can also be nested. As a result, you can use this module as a simple document store for storing semistructured data.

InfinityDB InfinityDB is an all-Java embedded DBMS with access like java.util.concurrent.ConcurrentNavigableMap over a tuple space, enhanced for nested Maps, LOBs, huge sparse arrays, wide tables with no size constraints. Transactions, compression, multi-core concurrency, easy schema evolution. Avoid the text/binary trap: strongly-typed, fine-grained access to big structures. 1M ops/sec. Commercial, closed source, patented.

KeyVast Key Value Store with scripting language. Data types include list, dictionary and set. Hierarchical keys. API: TCP/IP, Protocol: Query language, Written in: Delphi, License: MIT, Links: Github

SCR Siemens Common Repository In-Memory, scale-by-cell division (under load), multi-tiered scalability (transactions, entries, indicies), read=write, geo-redundancy, redundancy per datatype, LDAP, API, bulkload facility for VNF state resiliency, VNF-M integratable, self-[re-]balancing, Backend for Mobile Network Functions

IOWOW The C/C++ persistent key/value storage engine based on skip list data structure. API: C/C++. Protocol: Native. Written in: C11, Concurrency: RW locking. License: MIT

BBoxDB A distributed data store for multi-dimensional data. BBoxDB enhances the key-value data model by a bounding box, which describes the location of a value in an n-dimensional space. Data can be efficiently retrieved using hyper-rectangle queries. Spatial joins and dynamic data redistribution are also supported. API: Java, Protocol: asynchronous binary, Data model: Key-bounding-box-value, Scaling: Auto-Sharding, Replication, Written in: Java, Concurrency: eventually consistent / RW locking

NuSTER A HTTP based, user facing, RESTful NoSQL cache server based on HAProxy. It can be used as an internal NoSQL cache sits between your application and DBMS like Memcached or Redis as well as a user facing NoSQL cache that sits between end user and your application. It supports headers, cookies, so you can store per-user data to same endpoint. Protocol: HTTP. Written in: C.

JDX A lightweight in-memory document-oriented DBMS written with JavaScript. Includes Single Page Application API, node serialization, tree browsing and CRUD operations on document tuples through web GUI. Integrate with server-side noSQL DBMS instance into a transaction-synchronous cluster, create SPA content or browse and serialize document tuples with HTML interface.

Antidote Geo-replicated; multi-master; both reads & writes have local latency; sharded. Available under Partition (AP) with a high consistency (CP); MVCC; transactions; causal consistency (no ordering anomalies). API: CRDTs (= concurrent update, convergence). Protocol buffers, Erlang, JavaScript, Java, Go, REST. Ongoing work: same guarantees at edge; SQL-like language; static analysis; strong consistency on demand. Open source; written in Erlang. Publication: Cure

[SubRecord, Mo8onDb, Dovetaildb]

Graph Database Management Systems

Neo4J API: lots of langs, Protocol: Java embedded / REST, Query Method: Cypher, nativeJavaAPI, JRuby, Replication: typical MySQL style master/slave, Written in: Java, Concurrency: non-block reads, writes locks involved nodes/relationships until commit, Misc: ACID possible, Links: Video », Blog »

ArangoDB, FaunaDB, OrientDB, gunDB (Doc Store & GraphDB & Key-Value. More details in Category Multimodel Database Management Systems)

Infinite Graph (by Objectivity) API: Java, Protocol: Direct Language Binding, Query Method: Graph Navigation API, Predicate Language Qualification, Written in: Java (Core C++), Data Model: Labeled Directed Multi Graph, Concurrency: Update locking on subgraphs, concurrent non-blocking ingest, Misc: Free for Qualified Startups.

Sparksee (former DEX): API: Java, .NET, C++, Python, Objective-C, Blueprints Interface Protocol: Embedded, Query Method: as above + Gremlin (via Blueprints), Written in: C++, Data Model: Labeled Directed Attributed Multigraph, Concurrency: yes, Misc: ACID possible, Free community edition up to 1 Mio objects, Links: Intro », Technical Overview »

TITAN : API: Java, Blueprints, Gremlin, Python, Clojure Protocol: Thrift, RexPro(Binary), Rexster (HTTP/REST) Query Method: Gremlin, SPARQL Written In: Java Data Model: labeled Property Graph, directed, multi-graph adjacency list Concurrency: ACID Tunable C Replication: Multi-Master License: Apache 2 Pluggable backends: Cassandra, HBase, MapR M7 Tables, BDB, Persistit, Hazelcast Links: Titan User Group

InfoGrid API: Java, http/REST, Protocol: as API + XPRISO, OpenID, RSS, Atom, JSON, Java embedded, Query Method: Web user interface with html, RSS, Atom, JSON output, Java native, Replication: peer-to-peer, Written in: Java, Concurrency: concurrent reads, write lock within one MeshBase, Misc: Presentation »

HyperGraphDB API: Java (and Java Langs), Written in:Java, Query Method: Java or P2P, Replication: P2P, Concurrency: STM, Misc: Open-Source, Especially for AI and Semantic Web.

GraphBase Sub-graph-based API, query language, tools & transactions. Embedded Java, remote-proxy Java or REST. Distributed storage & processing. Read/write all Nodes. Permissions & Constraints frameworks. Object storage, vertex-embedded agents. Supports multiple graph models. Written in Java

Trinity API: C#, Protocol: C# Language Binding, Query Method: Graph Navigation API, Replication: P2P with Master Node, Written in: C#, Concurrency: Yes (Transactional update in online query mode, Non-blocking read in Batch Mode) Misc: distributed in-memory storage, parallel graph computation platform (Microsoft Research Project)

AllegroGraph API: Java, Python, Ruby, C#, Perl, Clojure, Lisp Protocol: REST, Query Method: SPARQL and Prolog, Libraries: Social Networking Analytics & GeoSpatial, Written in: Common Lisp, Links: Learning Center », Videos »

BrightstarDB A native, .NET, semantic web DBMS with code first Entity Framework, LINQ and OData support. API: C#, Protocol: SPARQL HTTP, C#, Query Method: LINQ, SPARQL, Written in: C#

Bigdata API: Java, Jini service discovery, Concurrency: very high (MVCC), Written in: Java, Misc: GPL + commercial, Data: RDF data with inference, dynamic key-range sharding of indices, Misc: Blog » (parallel DBMS, high-availability architecture, immortal DBMS with historical views)

Meronymy RDF enterprise database management system. It is cross-platform and can be used with most programming languages. Main features: high performance, guarantee database transactions with ACID, secure with ACL's, SPARQL & SPARUL, ODBC & JDBC drivers, RDF & RDFS. »

WhiteDB WhiteDB is a fast lightweight graph/N-tuples shared memory DBMS library written in C with focus on speed, portability and ease of use. Both for Linux and Windows, dual licensed with GPLv3 and a free nonrestrictive royalty-free commercial licence.

Onyx DBMS Graph/ORM high throughput DBMS built in Java supports embedded, in-memory, and remote. Horizontal scalability through sharding, partitioning, replication, and disaster recovery API: Java, REST via (Objective C, Android, etc...), Protocol: Java embedded/Binary Socket/REST, Query Method: Persistence Manager/ORM, Replication: Multicast, Written in: Java, Concurrency: Re-entrant read/write, Misc: Free and Open Source. Commercial licensing available Tutorials

OpenLink Virtuoso a/k/a Virtuoso Universal Server Multi-model (hybrid) DBMS supporting SQL/Tabular Relational (SQL), RDF/Graph Relational (SPARQL), XML (XPath, XQuery), Text/Document/Object, and more, available in Community (Open Source) and Enterprise (Commercial) Editions.

API: ODBC, JDBC, OLE DB, ADO.NET, JSON, RDF4J/Sesame, Redland, SPARQL, others;

Protocol: ODBC, JDBC, OLE DB, ADO.NET, HTTP, SPARQL, NNTP, IMAP, POP, LDP, others;

Query Method: SQL, SPARQL, SPARQL-in-SQL (SPASQL), SQL-in-SPARQL (via SQL/PSM), XPath, XQuery, others;

Replication (Enterprise Edition only): Star, Chain, and/or Bi-Directional Replication Clusters, as well as Shared-Nothing Elastic Clusters;

Written in: C/C++; extensible via C/C++, Java, Perl, Python, PHP, others;

Concurrency: ACID;

Misc: Role-Based Access Control (RBAC), Attribute-Based Access Control (ABAC)

Links: Virtuoso manual, Evolving Documentation. Open Source Project ODBC, JDBC, OLE DB, ADO.NET, JSON, RDF4J/Sesame, Redland, SPARQL, others;ODBC, JDBC, OLE DB, ADO.NET, HTTP, SPARQL, NNTP, IMAP, POP, LDP, others;SQL, SPARQL, SPARQL-in-SQL (SPASQL), SQL-in-SPARQL (via SQL/PSM), XPath, XQuery, others;Star, Chain, and/or Bi-Directional Replication Clusters, as well as Shared-Nothing Elastic Clusters;C/C++; extensible via C/C++, Java, Perl, Python, PHP, others;ACID;: Role-Based Access Control (RBAC), Attribute-Based Access Control (ABAC)

weaver scalable, fast, consistent

[Java Universal Network / Graph Framework, OpenRDF / Sesame, Filament, OWLim, NetworkX, iGraph, Jena]

List of SPARQL implementations can be found here

Multimodel Database Management Systems

ArangoDB API: REST, Graph Blueprints, C#, D, Ruby, Python, Java, PHP, Go, Python, etc. Data Model: Documents, Graphs and Key/Values. Protocol: HTTP using JSON. Query Method: declarative query language (AQL), query by example. Replication: master-slave (m-m to follow), Sharding: automatic and configurable Written in: C/C++/Javascript (V8 integrated), Concurrency: MVCC, tunable Misc: ACID transactions, microservices framework "Foxx" (Javascript), many indices as secondary, fulltext, geo, hash, Skip-list, capped collections

OpenLink Virtuoso a/k/a Virtuoso Universal Server Multi-model (hybrid) DBMS supporting SQL/Tabular Relational (SQL), RDF/Graph Relational (SPARQL), XML (XPath, XQuery), Text/Document/Object, and more, available in Community (Open Source) and Enterprise (Commercial) Editions.

API: ODBC, JDBC, OLE DB, ADO.NET, JSON, RDF4J/Sesame, Redland, SPARQL, others;

Protocol: ODBC, JDBC, OLE DB, ADO.NET, HTTP, SPARQL, NNTP, IMAP, POP, LDP, others;

Query Method: SQL, SPARQL, SPARQL-in-SQL (SPASQL), SQL-in-SPARQL (via SQL/PSM), XPath, XQuery, others;

Replication (Enterprise Edition only): Star, Chain, and/or Bi-Directional Replication Clusters, as well as Shared-Nothing Elastic Clusters;

Written in: C/C++; extensible via C/C++, Java, Perl, Python, PHP, others;

Concurrency: ACID; Misc: Role-Based Access Control (RBAC), Attribute-Based Access Control (ABAC)

Links: Virtuoso manual, Evolving Documentation. Open Source Project

OrientDB API: REST, Binary Protocol, Java, Node.js, Tinkerpop Blueprints, Python, PHP, Go, Elixir, etc., Schema: Has features of an Object DBMS, Document DBMS, Graph DBMS, and Key-Value DBMS, Written in: Java, Query Method: SQL, Gremlin, SparQL, Concurrency: MVCC, tunable, Indexing: Primary, Secondary, Composite indexes with support for Full-Text and Spatial, Replication: Master-Master + sharding, Misc: Really fast, Lightweight, ACID with recovery.

FaunaDB Packaging: Fully managed serverless cloud, or on-premise enterprise packages. API: HTTP, JavaScript, C#, Java, Ruby, Python, Swift, Android, Go, Python, Scala. Data Model: Documents, Graphs and Key/Values. Query Method: Fauna Query Language is optimized for expressing business transactions including precondition checks and control flow. Replication: active/active with global ACID transactions, Sharding: automatic Written in: Scala Concurrency: MVCC with configurable snapshot retention, all transactions are consistent. Misc: Multi-region ACID transactions, indexes, joins, and object level security.

FoundationDB Bought by Apple Inc. Closed and reopened for public access.

Datomic API: Many jvm languages, Protocol: Native + REST, Query Method: Datalog + custom extensions, Scaling: elastic via underlying DB (in-mem, DynamoDB, Riak, CouchBase, Infinispan, more to come), Written in: Clojure, Concurrency: ACID MISC: smart caching, unlimited read scalability, full-text search, cardinality, bi-directional refs 4 graph traversal, loves Clojure + Storm.

gunDB API: JavaScript Schema: Has features of an Object DBMS, Document DBMS, Graph DBMS, and Key-Value DBMS Written in: JavaScript Query Method: JavaScript Concurrency: Eventual consistency with hybrid vector/timestamp/lexical conflict resolution Indexing: O(1) key/value, supports multiple indices per record Replication: Multi-Master/Master; browser peer-to-peer (P2P) enabled Misc: Open source, realtime sync, offline-first, distributed/decentralized, graph-oriented, and fault-tolerant

CortexDB CortexDB is a dynamic schema-less multi-model data base providing nearly all advantages of up to now known NoSQL data base types (key-value store, document store, graph DB, multi-value DB, column DB) with dynamic re-organization during continuous operations, managing analytical and transaction data for agile software configuration,change requests on the fly, self service and low footprint.

Oracle NOSQL Database Oracle NoSQL Database is a distributed key-value DBMS with support for JSON docs. It is designed to provide highly reliable, scalable and available data storage across a configurable set of systems that function as storage nodes. NoSQL and the Enterprise Data is stored as key-value pairs, which are written to particular storage node(s), based on the hashed value of the primary key. Storage nodes are replicated to ensure high availability, rapid failover in the event of a node failure and optimal load balancing of queries. API: Java/C, Python, NodeJs, C#.

AlchemyDB GraphDB + RDBMS + KV Store + Document Store. Alchemy Database is a low-latency high-TPS NewSQL RDBMS embedded in the NOSQL datastore redis. Extensive datastore-side-scripting is provided via deeply embedded Lua. Bought and integrated with Aerospike.

WonderDB API:JDBC,SQL; WonderDB is fully transactional, distributed NewSQL DBMS implemented in java based on relational architectures. So you can get best of both worlds, sql, joins and ease of use from SQL and distribution, replication and sharding from NoSQL movement. Tested performance is over 60K per node with Amazon m3.xlarge VM.

RockallDB A new concept to ‘NoSQL’ DBMS where a memory allocator and a transactional DBMS are melted together into an almost seamless whole. The programming model uses variants of well-known memory allocation calls like ‘new’ and ‘delete’ to manage the database. The result is very fast, natural to use, reliable and scalable. It is especially good in Big Data, data collection, embedded, high performance, Internet of Things (IoT) or mobile type applications.