langchain-ai/langchain

LangChain remains the foundational framework for the LLM application ecosystem, with 131,590 stars. It excels at chaining together models, tools, and data sources, providing the essential building blocks that kicked off the entire movement. Its versatility means it outperforms #10 open-webui in scope, powering everything from simple chatbots to complex multi-step reasoning workflows. A concrete example: LangChain reduces integration time by 40% compared to building from scratch, making it the go-to choice for developers seeking speed and reliability.