Apache CouchDB

Apache CouchDB provides a document‑oriented database that synchronizes data across multiple primary nodes using its Couch Replication Protocol. The protocol works over standard HTTP and JSON, allowing data to flow between server clusters, mobile devices, and web browsers, which supports offline‑first applications and ensures eventual consistency even on unreliable networks.

The system can be deployed as a single‑node instance for simple workloads or scaled to a clustered configuration that offers higher capacity and high‑availability without changing the API. It includes a developer‑friendly query language and optional MapReduce for efficient data retrieval, and it natively stores JSON and binary data.

CouchDB is designed for reliability and flexibility, running on a range of hardware from small devices to large server farms, and it can be hosted on‑premises or on any major cloud provider. Its HTTP‑based interface makes it compatible with existing tools such as proxies and load balancers, facilitating integration into diverse application stacks.