This YouTube video explains how to build Retrieval Augmented Generation (RAG) applications using Langchain. The presenter covers Langchain's components, its growth, its position in the generative AI development stack, and its advantages. A practical demo showcases building a RAG application using Langchain and SingleStore as a vector database, highlighting how Langchain mitigates large language model hallucinations by accessing external knowledge sources for more accurate responses. This segment details the critical limitations of using LLMs solely for chatbot development. It points out the lack of access to current information, inability to verify accuracy, and limited integration with real-time data and business systems, setting the stage for the introduction of LangChain as a solution. This segment highlights the complexities of building AI applications, emphasizing the skills gap, the rapid evolution of the GenAI ecosystem, and the multifaceted challenges involved in data handling, model performance, and integration. It underscores that LLMs alone are insufficient for robust application development. This segment explains how RAG effectively addresses the issue of LLM hallucinations by using external knowledge sources to provide accurate and contextually relevant responses, contrasting the limitations of pre-trained LLMs with a real-world example of querying the 2024 Nobel Prize in Literature.This segment details Langchain's contribution to the RAG pipeline, highlighting its modules and tools for document processing, vector embedding creation, vector store integration, and LLM interaction, emphasizing the simplification it offers compared to manual development. This segment introduces the concept of Retrieval Augmented Generation (RAG) as a method to address the issue of hallucination in large language models. It explains the problem of LLMs generating factually incorrect or nonsensical responses and presents RAG as one of three key approaches (along with fine-tuning and prompt engineering) to mitigate this. This segment showcases LangChain's remarkable growth trajectory, using Google Trends and GitHub data to demonstrate its increasing popularity. It also includes a timeline highlighting key milestones, such as its initial release, viral tweets, and rapid increase in GitHub stars and valuation, illustrating its significant impact in the field. This segment demonstrates a practical tutorial on building RAG applications using Langchain and SingleStore as a vector database. It covers the steps of installing libraries, loading and splitting documents, creating vector embeddings, storing them in the database, and querying the data. This segment compares the LLM application development workflow with and without Langchain, showcasing how Langchain simplifies tasks such as authentication, rate limiting, prompt template creation, and vector store integration, reducing developer workload and complexity.