Testing Human in the Loop with LangGraph Example – Building a Fullstack Feedback Loop with FastAPI

Video Description

In this session, we walk through a fullstack example from LangGraph HITL – Building a Fullstack Feedback Loop with FastAPI and React, where LangGraph’s Human-in-the-Loop feature is integrated with a FastAPI backend and a simple ReactJS frontend. You’ll see how to pause and resume AI agent workflows, collect real user feedback, and update answers dynamically. It’s a practical demo for anyone building interactive AI agents using LangGraph, LangSmith, FastAPI, and modern web tools. I get it—tech content takes time to research, code, and polish. If my videos have helped you save time, avoid headaches, or just made debugging less painful, a coffee would be highly appreciated! https://buymeacoffee.com/grabduck 00:00 – Intro: Real-World HITL and Simple Graph Execution Limits 04:50 – Notebook Walkthrough: Defining the Graph and Handling Feedback Logic 09:30 – Step-by-Step Execution: Tracing Graph State in the Notebook 12:52 – Running the Full Feedback Loop in LangGraph Studio 14:57 – Building FastAPI Backend: Start & Resume Endpoints 18:28 – Testing Graph API with Swagger UI 22:25 – Final Thoughts: Fullstack Loop with LangGraph + FastAPI + React 🌟 Related Courses & Tutorials • LangGraph Into – Want to explore more about creating agentic AI application using LangGraph? Check out other videos in this tutorial series! https://youtube.com/playlist?list=PLaWfw53gNyzaZB3paLG0WmJPLSPj3idpS&si=PDeUvG_xELLrcG4g 💡 Explore More: Check out the GitHub repo with all the code we used in this session: https://github.com/esurovtsev/langgraph-hitl-fastapi-demo/tree/basic-blocking-api ============================= Hi, I’m Evgeny, a freelance software engineer passionate about solving complex problems with technologies like Java, Kotlin, Spring Boot, TypeScript, Python, and Node.js. On this channel, you’ll find content centered around AI, search technologies, and security, with in-depth coding sessions and theoretical discussions to enhance your knowledge. Join me as we explore the latest innovations in backend development and beyond. ============================= Just Meditate It is our own mindfulness & design brand. Operated by ECONOR s.r.o., Czech Republic. Legal Notice: Operated by ECONOR s.r.o., Czech Republic This channel and website are intended for an international English-speaking audience.