lark

Lark is an open‑source real‑time database server written primarily in Rust and built on the Glommio async runtime. It synchronizes a JSON tree across multiple clients, supporting optional persistence. The project includes a Go‑based edge component that terminates WebSocket, WebTransport, and REST HTTP connections, making it a drop‑in replacement for Firebase Realtime Database while preserving compatibility with Firebase client SDKs. Developers can run Lark locally using Docker images or compile from source, manage data via an admin dashboard, and back up the `lark-data` folder. The ecosystem provides a JavaScript client library (`@lark-sh/client`) for building real‑time web applications, example apps such as a multiplayer sticky‑notes whiteboard and a Firebase quickstart migration, and full documentation covering security rules, REST APIs, and SDK compatibility. Lark is used in production by Lark Cloud, undergoes rigorous durability testing, and follows an AGPL v3 license.