Master LLM apps, RAG, LangGraph, AI agents, local models, and real-world projects in 2026. LangChain adoption grew 60% YoY in 2025, powering RAG, multi-agent systems, and local LLM apps (Gartner, 2025). This data-driven ranked list of the 10 best-selling LangChain courses on Udemy uses real-time enrollments, 4.5+ …