K. Mitrov worked on core API features for GetStream’s stream-chat-js and stream-node repositories, focusing on scalable backend solutions using TypeScript and full stack development skills. He delivered a global app-level file upload and delete API, decoupling file management from channel logic to enable cross-channel workflows and improve code reuse. In stream-node, he enhanced the Feeds API by adding feed visibility management and ephemeral chat message updates, while refactoring the FeedResponse model to expose ownership and membership context directly. His work emphasized modular API design, robust request validation, and flexible integration patterns, addressing scalability and maintainability for complex applications.