Langflow

Langflow is an open-source, low-code visual platform for building AI agents and RAG applications (153,000+ GitHub stars) — a drag-and-drop interface for connecting LLMs, vector databases, and AI tools into working workflows. Who it's for: developers who want to build and iterate on multi-step AI/RAG workflows visually, with the option to drop into real Python code for advanced customization rather than being limited entirely to the visual builder. Strengths: a genuinely massive open-source community (153k+ stars) is real, checkable evidence of adoption, not a marketing claim, and support for major LLMs and vector databases means it isn't locked to one provider's ecosystem. Pre-built flows and reusable components speed up building common agent/RAG patterns rather than starting from a blank canvas every time. Weaknesses and limitations: visual, node-based workflow tools have their own learning curve, and for a very simple single-call use case, writing the code directly may be faster than building a visual flow. Real-world scenario: a developer wants to build and iterate quickly on a multi-step RAG or agent workflow, seeing the actual data flow visually rather than tracing through nested function calls in code.