LangChain is an open-source Python package aimed at making it easy to develop LLM-powered applications, initially addressing the challenge of getting a simple prototype working. However, as the technology has evolved, the main blocker for building production-ready applications has shifted from prototyping to performance issues such as application latency and token usage management. To address this, LangChain is introducing LangSmith, a platform designed to help developers close the gap between prototype and production by providing tools for debugging, testing, evaluating, and monitoring LLM applications. LangSmith offers features like full visibility into model inputs and outputs, easy dataset creation and management, intuitive UI for editing examples, and seamless integration with evaluation modules. The platform aims to provide a unified hub for managing LLM applications, streamlining the development process and enabling developers to build production-ready applications more efficiently.