Apache CouchDB vs BaseX

Apache CouchDB is a free document database that stores named documents and lets applications read and update them through a RESTful HTTP API. Documents can contain fields and binary attachments without following a fixed schema. Its query engine supports views made with JavaScript map functions and optional reduce functions. Incremental replication synchronizes databases in both directions between peers, including after disconnections; the project describes this as useful for offline-first applications across servers, phones, and browsers. PouchDB can replicate with CouchDB from mobile devices and web browsers. A cluster can present one logical database across multiple servers or virtual machines for added capacity and high availability. CouchDB uses an append-only file design, and its documentation describes document updates as ACID and all-or-nothing. Security features include administrator accounts, basic and cookie authentication, reader access controls, and JavaScript validation of document updates. Replicas may retain conflicting revisions for manual or automated resolution. CouchDB is self-hosted on servers or virtual machines, as a single node or cluster, and is licensed under Apache License 2.0.

BaseX is a free, open-source XML database engine and XQuery processor for data-intensive web applications. It stores XML documents, binary data, and XQuery values, and handles XML, HTML, JSON, and CSV formats. Its XQuery 4.0 processor supports the W3C Update and Full Text extensions. You can operate it from the command line, in client/server mode, or through desktop and web interfaces. The graphical interface provides a query editor with syntax highlighting, keyword search, interactive visualizations, and server administration. RESTXQ supports building web applications with XQuery, while the server offers REST and WebDAV access to databases and resources. Concurrent reads, ACID-safe write transactions, user permissions, and secure authentication are supported. BaseX runs on Linux, macOS, and Windows, with API and self-hosted deployment listed. Java 17 or higher is required, and Adoptium distributions are recommended. The BaseX plan costs nothing.