Express.js GET & POST Requests Tutorial: Build & Test APIs with Postman & Body-Parser

Learn how to build, test, and connect GET and POST endpoints in Node.js and Express.js step by step! In this practical full-length tutorial, we build a real chat messaging backend from scratch, connect it to frontend AJAX calls using jQuery, and test API endpoints using Postman. We also tackle real-world development roadblocks, including fixing the common Express "req.body is undefined" error using body-parser middleware! 📌 What You Will Learn: Setting up GET routes in Express (`app.get`) Fetching backend data using jQuery AJAX (`$.get`) Handling client-side rendering with dynamic DOM updates Setting up POST endpoints in Express (`app.post`) Testing raw JSON requests and status codes (200 OK) in Postman Installing and configuring `body-parser` middleware (`json` & `urlencoded`) Sending POST requests directly from frontend forms/textareas ⏱️ Timestamps & Chapters: 00:00 - Introduction & Project Overview 00:10 - Creating GET Messages Endpoint in Express (`server.js`) 03:10 - Testing GET Endpoint & Returning Hello World String 05:00 - Mocking Backend Data with Message Objects & Arrays 09:20 - Connecting Frontend UI to GET Service with jQuery AJAX 14:55 - Troubleshooting jQuery Slim CDN & $ Not Defined Error 17:09 - Creating POST Messages Endpoint in Express 19:38 - Testing POST Requests & Status Codes in Postman 22:08 - Debugging `req.body undefined`: Express Body Parsing Issue 22:45 - Installing & Configuring `body-parser` Middleware 26:40 - Successfully Parsing JSON Payloads via Postman 29:32 - Connecting Frontend UI to Send POST Requests 33:10 - Updating Form Controls (`input` vs `textarea`) & IDs 36:40 - Writing jQuery `postMessage` Function & DOM Binding 39:45 - Handling Form URL-Encoded Requests with `body-parser` 41:10 - Final Live Demo: Full End-to-End Chat Messaging App 💻 Tech Stack Used: Node.js & Express.js jQuery AJAX Postman API Platform Body-Parser Middleware 🔔 Subscribe to FreePlacementCourse for more comprehensive tutorials on web development, placement preparation, and coding projects! #ExpressJS #NodeJS #WebDevelopment #Postman #RESTAPI #JavaScript #BackendDevelopment