Langflow

Langflow has become one of the go-to low-code platforms for prototyping and shipping agentic and RAG applications, pairing a visual flow builder with the ability to drop into raw Python whenever the no-code abstraction isn't enough. Its component library spans nearly every popular LLM provider, vector database, and data connector, which makes it genuinely useful for teams who want to move from notebook experiments to a deployable API without reinventing plumbing each time. The tradeoff is that complex flows can become visually tangled, and getting the most out of self-hosted deployments still demands some DevOps comfort, but as a free, open-source foundation for agent building it punches well above its price point.