LangChain Has a Free API — Here's How to Build AI Agents That Use Tools and Memory

Why LangChain? LangChain is the framework for building LLM-powered applications . It provides chains, agents, RAG pipelines, memory, and tool integration — connecting LLMs to your data and the real world. Free and open source. LangSmith (observability) has a free tier: 5K traces/month. Getting Started pip install langchain langchain-openai Simple Chain from langchain_openai import ChatOpenAI from langchain_core.prompts import ChatPromptTemplate llm = ChatOpenAI ( model = " gpt-4o " ) prompt = ChatPromptTemplate . from_messages ([ ( " system " , " You are a helpful assistant that explains {topic} simply. " ), ( " human " , " {question} " ) ]) chain = prompt | llm result = chain . invoke ({ " topic " : " databases " , " question " : " What is a vector database? " }) print ( result . content ) RAG (Retrieval Augmented Generation) from langchain_community.document_loaders import WebBaseLoader from langchain_text_splitters import RecursiveCharacterTextSplitter from langchain_community.vecto