Lark
Lark is an open-source realtime database that synchronizes persistent state across thousands of users while supporting fast-twitch, volatile data for ephemeral interactions like cursor positions and typing indicators. It is 100% drop-in compatible with Firebase RTDB, requiring only a single config change to migrate. The platform offers self-hosting under an AGPL license or a managed cloud option with metered billing starting at $10/month.
- Developer Tools
- Software Only
Funding
Funding not disclosed
Founders
Founder details are not available yet.
Product
Problem
Developers building realtime applications often rely on proprietary database services that lock them into a specific vendor, limit data ownership, and require complex migration paths. Existing realtime solutions may struggle to handle high-frequency updates like cursor positions and typing indicators alongside persistent state, forcing developers to maintain separate systems for different data types.
Solution
Lark provides an open-source realtime database that synchronizes persistent state across thousands of users while also supporting fast-twitch, volatile data for ephemeral interactions. The platform is 100% drop-in compatible with Firebase RTDB, allowing developers to migrate by changing a single config variable. Lark supports presence and volatile paths for features like typing indicators and cursor movement, using the same SDK patterns developers already know. The entire server is available on GitHub under an AGPL license, enabling self-hosting, while Lark Cloud offers a managed alternative powered by the same codebase.
Target Audience
Primary users are developers building web apps, mobile apps, and games that require realtime data synchronization, particularly those currently using Firebase RTDB who want an open-source or self-hosted alternative.
Features
- 100% drop-in compatibility with Firebase RTDB, requiring only a single config change for migration
- Volatile Paths for high-frequency, fire-and-forget data like cursors and game state, billed at 1/5th the standard bandwidth rate
- Presence support for realtime user status and activity indicators
- Client SDKs for JavaScript, TypeScript, React, Node.js, Swift, Kotlin, iOS, Android, Unity, Flutter, C#, and REST API
- Open-source server under AGPL license, allowing self-hosting, forking, and auditing
- Cloud hosting option with metered billing for storage and bandwidth, no per-connection charges