RxDB

RxDB is a local-first NoSQL database for JavaScript applications that runs directly in the app process, delivering zero-latency queries even when offline and synchronizing seamlessly with any backend. The project has accumulated over 22,800 GitHub stars and is recognized as a MongoDB Official Partner and a Supabase Official Partner. The core philosophy is local-first architecture, where data is stored on the client device using IndexedDB, OPFS, local storage, SQLite, or in-memory adapters, enabling instant reads and writes without network round-trips. When connectivity returns, the built-in replication protocol synchronizes with backends including GraphQL, Firebase, Supabase, MongoDB, NATS, HTTP, CouchDB, WebRTC, Appwrite, Google Drive, and Microsoft OneDrive through pluggable replication engines. Observable realtime queries automatically push updates to UI components when underlying data changes, eliminating manual refetch logic. The database supports all major JavaScript runtimes including React, Angular, Vue, Svelte, Node.js, Deno, Electron, Ionic, NativeScript, React Native, Expo, and Flutter. Conflict resolution uses deterministic CRDT-based merging to guarantee consistency across multi-device edits. Production users include Readwise, SafeEx, WebWare, myAgro, MoreApp, ALTGRAS, WooCommerce POS, atroo GmbH, and Nutrien. The community spans over 1,300 Discord members and active contributors. Additional features include encryption at rest, schema validation with TypeScript types, migration strategies, query caching with TTL, offline first pagination, and a comprehensive testing suite with over 3,000 unit tests ensuring stability across all supported storage engines.