FastAPI Full Crash Course with GenAI & LangChain | Build & Deploy an AI Agent as a REST API (2026)

In this complete FastAPI + GenAI crash course, you'll learn everything from the absolute basics of APIs to building and deploying a real AI Agent as a REST API! 🔥 What you'll learn: ✅ What is an API & how Frontend-Backend-Database communication works ✅ HTTP Protocol, Routes, Path Params & Query Params explained ✅ HTTP Methods (GET, POST, PUT, DELETE) & CRUD Operations ✅ Building a complete Product CRUD API using FastAPI ✅ Data validation using Pydantic (DTOs & Schemas) ✅ HTTP Status Codes & Custom Exception Handling ✅ Sending Emails from FastAPI using FastAPI-Mail ✅ Running long tasks efficiently using Background Tasks ✅ Introduction to Generative AI & Large Language Models (LLMs) ✅ Connecting LLMs using LangChain ✅ Using Groq API for ultra-fast, free LLM inference ✅ Building an AI Agent with Tools (Google Search integration) ✅ Deploying your AI Agent as a REST API using LangServe ✅ Connecting your Agent to LangGraph Studio & Agent Chat UI By the end of this video, you'll have built a fully functional GenAI-powered REST API — combining traditional backend development with modern AI Agent architecture. ⏱️ Timestamps: 00:00 Introduction 02:10 Frontend vs Backend Explained 08:24 HTTP, Routes, Ports & CRUD Basics 15:23 FastAPI Installation & Setup 29:14 Building the Product CRUD API 44:24 Path Params & Query Params 52:25 HTTP Status Codes & Error Handling 01:01:45 Pydantic DTOs and Complete CRUD Apis 01:32:57 Sending Emails via FastAPI-Mail 01:52:19 Background Tasks in FastAPI 02:03:33 What is Generative AI & LLMs? 02:10:32 Connecting LLMs with LangChain & Groq 02:26:00 What is an AI Agent? 02:32:15 Building an Agent with Tools 02:37:52 Deploying Agent as REST API (LangServe) 02:47:50 Connecting to Agent Chat UI 02:50:04 Final Recap 📌 Tech Stack Used: Python, FastAPI, Pydantic, FastAPI-Mail, LangChain, Groq API, LangServe, LangGraph 👉 If you found this helpful, don't forget to LIKE, SHARE & SUBSCRIBE to Tech Plus Learnings for more hands-on tutorials on Python, Backend Development & Generative AI! #FastAPI #LangChain #GenerativeAI #Python #BackendDevelopment #AIAgents #Groq #RESTAPI #TechPlusLearnings #genai #gemini #agent #agenticai #crashcourse #fastapitutorial