MobileIMSDK is an open-source instant messaging framework that provides reliable real-time message delivery across iOS, Android, Java, HarmonyOS, and web platforms. At its core, it offers a unified communication layer that transparently supports UDP, TCP, and WebSocket transports, enabling developers to send and receive messages without managing protocol differences or connection state. The framework includes an automatic reconnection engine that detects network outages and restores connections without manual intervention, with built-in message retransmission and deduplication to guarantee exactly-once delivery.
The server component is built on Netty, handling millions of concurrent connections for push scenarios and tens of thousands for chat applications. Client SDKs for each platform expose a consistent API, wrapping the core protocol in platform-specific implementations. The framework maintains per-client session state on the server to track connection lifecycle, message ordering, and offline buffering, while lightweight binary serialization minimizes bandwidth and parsing overhead on mobile and embedded clients.
The project provides a complete cross-platform instant messaging solution with automatic network resilience, multi-protocol transport abstraction, and high-concurrency server infrastructure. Documentation covers installation, API reference, and platform-specific integration guides for all supported environments.