The world is evolving toward Large Language Models (LLMs), and every company wants to embrace the power of generative AI. LangChain is an open-source AI framework that simplifies building custom AI applications using LLMs, reducing coding complexity and innovation by providing application's building blocks and components. It bridges the gap between LLMs and real-world applications, facilitating the integration of language models with external databases, logic, APIs, etc., enhancing the capabilities of LLMs' problem-solving strategies. LangChain is composed of six modules/components: Large Language Models, Prompt construction, Conversational memory, Intelligent agents, Indexes, and Chains. It provides a standard interface and some commonly used implementations for chaining LLMs together for more complex applications. The framework's adoption is skyrocketing due to the advantages it provides over traditional frameworks that are more complex. LangChain can be used to build AI applications such as chatbots, document analysis, and text search by leveraging the power of LLMs and vector databases.