Apache CouchDB vs JayDB

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.

JayDB is a JSON document database with per-user sign-in, aimed at static apps that need user, session, or tenant data without an app-owned backend. Documents are JSON at slash-separated paths, and the first write creates the namespace. Its REST data plane supports GET, PUT, DELETE, and prefix listing. Browser apps can authenticate through OIDC with Authorization Code and PKCE without embedding a client secret. Listed identity providers include Google, GitHub, Microsoft, generic OIDC, and custom OAuth2. The official SDK supports authentication, token refresh, typed document access, and compare-and-swap operations. ETag-based compare-and-swap may reject a write with HTTP 412 if the document changed since it was read. JayDB is available as managed cloud software or as a self-hosted Go engine under the MIT license, using S3-compatible storage or local disk. The free plan is free and includes 1 GB stored, 100,000 reads per month, and 10,000 writes per month; usage hard-stops at those allowances. Metered rates are $0.05 per GB-month of storage, $0.20 per million reads, and $0.50 per million writes.