The LangChain team has introduced the LangChain Expression Language (LCEL), a new syntax designed to enhance the composition of chains, offering built-in support for batch, async, and streaming operations. LCEL aims to simplify the construction of complex chains, complementing the LangSmith platform that facilitates the transition from prototype to production. The concept of chaining, which involves making multiple language model calls, combining data transformation with LLM calls, or passing LLM outputs to downstream applications, is popular in building language model applications. The introduction of LCEL provides a declarative approach to composing chains, improving usability and making it easier to customize components and modify prompts. This innovation integrates seamlessly with LangSmith, automatically ensuring correct callback tracing. The LangChain team has developed a "LangChain Teacher" application to help users learn LCEL and will conduct a webinar to further introduce this new tool. LangChain is actively seeking contributors to expand its functionality, encouraging interested individuals to participate by submitting pull requests.