LangChain templates are an essential tool for building production-ready Language Learning Model (LLM) applications. This tutorial provides a step-by-step guide on how to install and run these templates, modify them for specific use cases, and deploy them as REST APIs using FastAPI. The video begins with an introduction to LangChain templates, explaining their role as a reference architecture and how they can be deployed with LangServe. It then moves on to the installation and running of the templates, providing detailed instructions and insights. The tutorial also covers how to modify the templates for specific use cases, such as loading documents from URLs or directories, customizing the application to use specific documents, and debugging applications using the playground interface. The final section of the tutorial focuses on accessing and testing the deployed application using a Python client. It demonstrates how to invoke the application to answer specific questions and the use of invoke and batch endpoints. This tutorial is a must-watch for anyone looking to leverage LangChain templates for their LLM applications.