Dify is an open-source LLMOps platform developed by LangGenius, Inc. that provides a comprehensive environment for building AI-powered applications. With over 60,000 GitHub stars, it is one of the most popular open-source AI application platforms. Dify combines a visual workflow builder, RAG (Retrieval-Augmented Generation) pipeline engine, AI agent framework, and model management into a single unified interface. Users can drag and drop to visually create AI apps and workflows capable of diverse tasks. The platform supports accessing, switching, and comparing performance across different LLMs worldwide, including both open-source and proprietary models. Agent capabilities include defining agents based on LLM Function Calling or ReAct frameworks, with 50+ built-in tools including Google Search, DALL-E, Stable Diffusion, and WolframAlpha. Dify supports MCP (Model Context Protocol) for connecting to external APIs, databases, and services through standardized protocols. The platform can be self-hosted for free with no license fees, making it particularly attractive for organizations that need data sovereignty. Cloud pricing ranges from a free Sandbox tier to $159 per month for Teams, with custom Enterprise pricing available. Dify is free for students and educators.