Couchbase

Couchbase is a distributed NoSQL document-oriented database designed for latency-sensitive, interactive applications. It stores data as JSON documents and offers fast key-value access along with a SQL-like query layer. Originating from the merger of Membase and CouchOne, Couchbase combines in-memory caching with durable storage to deliver low-latency reads and writes, elastic horizontal scalability, and high availability across multi-node clusters and data centers.

The system uses a shared-nothing architecture with data partitioned across nodes. A cluster runs multiple services: Data Service for storage, Index Service for secondary indexes, Query Service for N1QL queries, Analytics Service for large-scale processing, and a Full-Text Search Service. It supports cross-datacenter replication for disaster recovery and a mobile/edge synchronization layer via Sync Gateway and Couchbase Lite for offline-capable apps.

Query is performed with N1QL, a SQL-like language for JSON documents. Access is available through language SDKs, REST management APIs, and tunable durability and consistency settings that control replication and disk persistence.

Couchbase is available in Community and Enterprise editions, with the Enterprise edition adding features such as cross-datacenter replication, analytics, and enhanced security. Common use cases include caching, session stores, product catalogs, user profiles, shopping carts, and real-time analytics, all requiring low latency and scalable storage.