Langflow is a full-stack, open-source platform for building and deploying AI-powered agents and workflows. It provides a visual flow builder (React frontend), a Python backend (FastAPI/SQLModel), a CLI executor (LFX), an MCP server for AI tool integration, and a Python SDK. The codebase is a monorepo with multiple packages: the main `langflow` distribution, `langflow-base` (core backend), `lfx` (lightweight executor/CLI), `langflow-sdk` (API client), `langflow-stepflow` (step-based execution), and extension bundles (e.g., lfx-duckduckgo, lfx-arxiv, lfx-ibm, lfx-docling). The backend uses SQLModel with Alembic migrations, Celery for background tasks, FastAPI for REST endpoints, and a plugin/extension system for bundles. The frontend is a React/TypeScript app built with Vite, React Flow, Zustand, and Tailwind. The architecture supports multi-worker deployments, auto-login, JWT auth, rate limiting, MCP server integration, and a rich component library for LLMs, vector stores, tools, and data processing.