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- Responsible for the development of core modules in the IM backend, including but not limited to: one-on-one chat / group chat, message synchronization, historical messages, offline messages, acknowledgment mechanisms, editing historical messages, and read/unread status.

- Design and develop backend services for the instant messaging system, including message delivery, session management, message storage, offline messages, file management, and push notifications.

- Optimize the stability and real-time performance of message channels (such as WebSocket, MQTT, etc.) under different network environments.

- Responsible for core logic including user status management, message deduplication and idempotency, message acknowledgment, and read status synchronization.

- Collaborate with the client team to define interface protocols and data structures (such as ProtoBuf, JSON, MsgPack, etc.).

- Build a high-performance, highly available system architecture that supports millions of concurrent online users.

- Participate in the development of operational tools, log monitoring, and anomaly warning systems to enhance overall system stability.

- Proficient in a mainstream server-side programming language (Go / C++ / Java / Rust / Node.js, etc.), with strong coding structure and engineering capabilities.

- Familiar with common communication protocols and technologies, such as WebSocket, MQTT, HTTP/2, gRPC, long connection management, etc.

- Knowledgeable in distributed caching (Redis) and database (MySQL / MongoDB / ClickHouse, etc.) design and optimization.

- Experience with service deployment and containerization (such as Docker / Kubernetes) is preferred.

3. Preferred Qualifications

- Experience in developing an IM system (such as one-on-one chat/group chat/audio and video/ephemeral messaging, etc.).

- Familiar with Signal protocol, Matrix protocol, XMPP, or Web3 communication protocols (such as Waku, Lens Protocol).

- Experience in real-time audio and video communication (WebRTC, SFU, TURN, etc.) projects.

- Capable of service governance, grayscale release, traffic limiting, and circuit breaking operations support.